NZ251267A

NZ251267A - 1-(3-amino-2-hydroxy-4-phenylbutyl)piperidine-2-carboxamide (pipecolinic acid) derivatives and pharmaceutical compositions

Info

Publication number: NZ251267A
Application number: NZ251267A
Authority: NZ
Inventors: Paul Cates Anderson; Francois Soucy; Christianne Yoakim; Pierre Lavalle; Peirre Louise Beaulieu
Original assignee: Bio Mega Boehringer Ingelheim
Priority date: 1992-03-13
Filing date: 1993-03-12
Publication date: 1996-09-25
Also published as: ZA931776B; JP3258422B2; IL105035A0; HU211854A9; CA2131185A1; NO943383L; ES2066623T3; US5807870A; HUT70617A; OA10092A; DE69300043D1; FI944217A; WO1993018003A1; NO943383D0; HU9402613D0; PL176362B1; DK0560268T3; CZ223294A3; AU670582B2; SK109094A3

Description

<div class="application article clearfix" id="description"> New Zealand Paient Spedficaiion for Paient Number £51 267 25 1 2 6 7 Mew Zealand Mo. 251267 International No. PCT/CA93/00096 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates: 1313^3. International fliing date: Classification: JPCb'. Col3)2.11/bo; CoT3>HOl/ia, »4-; P>blK3l )M4-, 1+7, 5oS Publication date: 15 SEP 1996 Journal No.: 14-OS NO DRAWINGS NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of invention: Substituted pipecolinic acid derivatives as HIV protease inhibitors Name, address and nationality of applicajit(s) as in international application form: Bio-Mega/Boehringer Ingelheim Research Inc. of 2100 ftue Cunard, Laval, Quebec H7S 2G5, Canada A (Tonacito.o Corv^cri^, WO 93/18003 1 251267 PCT/CA93/00096 Substituted Pipecolinic Acid Derivatives As HIV Protease Inhibitors Field of Invention 5 This invention relates to compounds exhibiting activity against particular retroviruses, to processes for producing the compounds, to pharmaceutical preparations thereof, and to a method 10 of using the compounds to combat infections caused by the retroviruses. Background of the Invention 15 In 1983, a retrovirus, known as human immunodeficiency virus type 1 (HIV-1), was established as a causative agent of acquired immune deficiency syndrome (AIDS), see R.C. Gallo and L. Montagnier, Scientific American, 259 (4), 40 (1988). 20 This virus has become a pestilence of alarming proportion. More recently, the closely related virus, human immunodeficiency virus type 2 (HIV-2) has been identified as a second causative agent of AIDS. 25 The identification of human immunodeficiency virus (HIV) as a causative agent and the development of methods to grow the virus in quantity have resulted in the discovery of compounds which inhibit 30 the replication of HIV in vitro. The most important class of inhibitor compounds identified in this manner is a group of dideoxynucleosides cl which 3/-azido-S'-deoxythymidine (known also zs zidovudine or AZT) and, more recently, 7.', S'-dirieoxyinosine (known 35 also as didanosine or DDI) are used therapeutically to manage certain patients with symptomatic HIV 25 12 67 WO 93/18003 PCT/CA93/0009^ infections. This class of compounds has been found to interfere with the life cycle of HIV by inhibiting reverse transcriptase. This enzyme converts viral RNA to double-stranded 5 deoxyribonucleic acid (DNA) and as such is an essential enzyme for HIV replication. In addition to inhibiting reverse transcriptase, other stages of the HIV life cycle have been identified as targets for developing anti-AIDS drugs. One target that is 10 receiving increased attention is an HIV-encoded enzyme known as HIV protease. This enzyme, like the reverse transcriptase, is encoded by the pol gene and is essential for HIV growth. It is responsible for effecting certain cleavages within the gag (p55) 15 or gag-pol (pl80) proteins to release structural proteins, e.g. pl7 and p24, and enzymes, including itself, found in mature infectious virions. Thus, inhibitors of HIV protease can block the HIV life cycle. 20 The increased attention given to HIV protease over the last' few years is reflected in the increase in reports o4 the discovery of agents which block the enzyme. See, for example, the recent review on 25 protease inhibitors by D.W Norbeck and D. J. Kempf, Annual Reports In Medicinal Chemistry, 2&t 141 (1991). As noted in the latter review and reported by D. H. Rich et al., J. Med. Chem., 13, 1285 (1990) and N.A. Roberts et al., Science, 248. 358 (1990), 30 two potent series of HIV protease inhibitors have been realized by the placement of a hydroxyethylamine transition state analog (TSA) in a peptide having the pl7/p24 substrate cleavage site sequence. Biological investigations of lead 35 compounds of the Roberts et al. series have been 3 251 267 reported by H.A. Overton et al., Virology, 179. 508 (1990), J.A. Martin et al., Biochem. Biophys. Res. Commun., 176. 180 (1991) and J.C. Craig et al., Antiviral- Chemistry .and Chemotheraphy, 2., 181 5 (1991). Other disclosures of HIV protease inhibitors having a hydroxyethylamine TSA includes 10 B.K. Handa et al., European patent application 34 6 847, published December 20, 1989, G.B. Dreyer et al., European patent application 352 000, published January 24, 1990, 15 D.J. Kempf et al., European patent application 402 646, published December 19, 1990, K.E.B. Parkes et al., Canadian patent application 20 2,030,415, published June 12, 1991, and J. A. Martin and S. Redshaw, European patent application 432 695, published June 19, 1!)91. 25 The present application discloses pipecolinic acid derivatives having an ethylamine TSA incorporated therein. The derivatives are potent inhibitors of HIV protease. Moreover, a capacity to inhibit HIV induced cytopathogenic effects in human 30 cells has been demonstrated for the compounds. Such properties, together with the attributes of a relatively selective action and an apparent lack of toxicity, renders the compounds useful as agents for combating HIV infections. 35 ; j.Z. PATENT OFFICE - 9 JUL « RECEiVED 25 12 67 WO 93/18003 PCT/CA93/000p Summary of the Invention The compounds of this invention are represented by formula 1 10 X-B-N C(0)NHR 15 1 wherein X is R30C(0), R3C(0) or R3NR4C(0) wherein R3 is (i) lower alkyl, (ii) lower cycloalkyl, 20 (iii)phenyl; phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; or disubstituted phenyl wherein each of the two substituent is independently lower alkyl or halo; 25 (iv) phenyl(lower)alkyl or phenyl(lower)alkyl wherein the aromatic portion thereof is monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy, 30 (v) 1-naphthyl or 2-naphthyl, (vi) (Het) or (Het)-(lower alkyl) wherein Het represents a five or six membered, monovalent heterocyclic radical containing one or two hetero- 35 atoms selected from nitrogen, oxygen and sulfur, or (vii)2-guinolinyl or 3-quinolinyl, and R4 is hydrogen or lower alkyl? or 5 10 15 20 25 30 251 2 57 X is R3*OCH2C(C>) wherein R3* is phenyl or monosubstituted, disubstituted or trisubstituted phenyl wherein each substituent is independently lower alkyl or halo; B is absent or the divalent radical -NHCHR5C{0)~ wherein R5 is lower alkyl; lower cycloalkyl; (lower cycloalkyl)-(lower alkyl); phenylmethyl; or lower alkyl monosubstituted with hydroxy, carboxy, lower alkoxycarbonyl, aminocarbonyl, (lower alkyl)amino-carbonyl or di(lower alkyl)aminocarbonyl; R1 is hydrogen, halo, hydroxy, lower alkyl or lower alkoxy; R2 is lower alkyl; and Y is lower alkyl; lower cycloalkyl; phenyl or phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; benzyl or benzyl inonosubstitued with halo, hydroxy, lower alkyl or lower alkoxy; or Y is W(CH2)nZ wherein W is oxo, thio, sulfinyl or sulfonyl, Z is lower alkyl; phenyl or phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; or (Het) wherein (Het) is as defined hereinbefore; and n is zero or one; or a therapeutically acceptable acid addition salt thereof. It is to be understood that the term "B is absent", used herein with reference to formula 1, means that the symbol B has become a covalent bond joining "X" to the secondary amino group which otherwise would be joined to "B". A preferred group of compounds of the invention is represented by formula 1 wherein X is R30C(0), R3C(0) or R3NR4C(0) wherein R3 is lower alkyl, f o JUL 1996w 2 5 1:2 6 7 6 phenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 2,4-dichlorophenyl, 2,5-dichlorophenyl, 2,6-difluoro-phenyl, 5-fluoro-2-methylphenyl, phenyl(lower)alkyl, phenyl(lower)alkyl wherein position 4 of the phenyl portion is substituted with chloro, fluoro, hydroxy, methyl or methoxy, 1-naphthyl, 2~naphthyl, 2-furyl, 2-thienyl, 2-pyridinyl/ 4-pyridinyl, 2-pyridinyl-methyl, 4-thiazolylmethyl or 2-auinolinyl, and R4 is hydrogen or lower alkyl;or X is R3AOCH2C(0) wherein R3X is phenyl or phenyl mono-, di- or trisubstituted with lower alkyl or halo at a position or positions selected from the group consisting of positions 2, 4 and 6; B is absent or is the divalent radical -NHCHRsC(0)-wherein R5 is lower alkyl, or lower alkyl monosubsituted with hydroxy, lower alkoxycarbonyl, aminocarbonyl, (lower alkyl)aminocarbonyl or di(lower alkyl)aminocarbonyl; R1 is hydrogen, chloro, bromo or fluoro; R2 is 1-methylethyl, 2-methylpropyl or 1,1-dimethylethyl; and Y is lower cycloalkyl, phenyl, 4-chlorophenyl, 4-bromophenyl, 4-fluorophenyl, 4-methylphenylf 4-methoxyphenyl, benzyl, (4-fluorophenyl)methyl, (4-methoxyphenyl)methyl or (4-methylphenyl) methyl; or ~Y is W(CH2)nZ wherein W and n are as defined hereinabove and Z is lower alkyl, phenyl, 2-furyl, 2-thienyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 4-thiazolyl, 2-pyrimidinyl, 4-methyl-2-pyrimidinyl, 4,6-dimethyl-2-pyrimidinyl or 2,6-dimethyl-4-pyrimidinyl; or a therapeutically acceptable acid addition salt thereof. A more preferred group of compounds is represented by formula 1 wherein X J 7 25-1 2 67 butyloxycarbonyl, ^ (2,6-dimethylphenyl )carbonyl, (2,4-dichloropheny1)carbonyl, (2,5-dichlorophenyl) -carbonyl, (2,6-difluorophenyl)carbonyl, (5-fluoro-2-methylphenyl)carbonyl, .benzyloxycarbonyl, (4-chloro-pheny 1) methoxycarbony 1, (4 -hydroxyphenyl) methoxy-carbonyl, (4-methoxyphenyl)methoxycarbonyl, acetyl, benzoyl, 1-naphthalenylcarbonyl, 2-naphthalen-ylcarbonyl, (2-pyridinylmethoxy)carbonyl, 2- quinolinylcarbonyl, bsnzylaminocarbonyl, N-(2-pyridinylmethyl)aminocarbonyl, N-methyl-N-(2- pyridinylmethyl)aminocarbonyl, phenoxyacetyl, (2-methy lphenoxy) acetyl, (2,4 -dime thy lphenoxy) acetyl, (2,6-dimethy lphenoxy) acetyl, (2,4,6-trimethylphen-oxyjacetyl, (4-chlorophenoxy)acetyl or (4-fluoro-2,6-dimethylphenoxy)acetyl; B is absent or the divalent radical -HHCHRsC(0)-wherein Rs is 1-methylethyl, 1,1-dimethylethyl, 1-methylpropyl, 2-methylpropyl, 1-hydroxyethyl, (methoxycarbonyl) methyl, (ethoxycarbonyl) methyl, (aminocarbonyl)methyl or { (methylamino)carbonyl}-methyl; R1 is hydrogen or fluorine; R2 is 2-methylpropyl or 1,1-dimethylethyl; and Y is cyclohexyl, phenyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, benzyl, (4-methy lpheny 1)methyl, (4-methoxypheny 1)-methyl, 2-methylpropoxy, phenoxy, 2-pyridinyloxy, 3-pyridinyloxy, 4-pyridinyloxy, 2-pyrimidinyloxy, (4-methyl-2-pyriniidinyl )oxy, (4,6-dimethyl-2-pyrimidin-yl)oxy, (2,6-dimethyl-4-pyrimidinyl)oxy, benzyloxy, 2-pyridinylmethoxy, 3-pyridinylmethoxy, 4- pyridinylmethoxy, 4-thiazolylmethoxy, phenylthio, phenylsulfinyl, phenylsulfonyl, 2-pyridinylthio, 3-pyridinylthio, 4-pyridinylthio, 2-pyrimidinylthio, (4-methyl-2-pyrimidinyl)thio, (2,6-dimethyl-4- pyrimi-dinyl)thio, (4, 6-dimethyl-2-pyrimidinyl)thio, benzylthio, benzylsulfinyl, benzyl sulfonyl^^^^,^ A* ,'/n- c i* 9 JUL (996 251267 WO 93/18003 PCT/CA93/000? 8 pyridinylmethyl)thio, (3-pyridinylmethyl)thio or (4-pyridinylmethyl)thio; or a therapeutically acceptable acid addition salt. 5 A most preferred group of the compounds is represented by formula 1 in which X is tert-butyloxycarbonyl, benzyloxycarbonyl, acetyl, (2,6-dimethylphenyl)carbonyl, 2-naphthalenylcarbonyl, (2-pyridinylmethoxy)carbonyl, 2-guinolinylcarbonyl or 10 {N-methyl-N-(2-pyridinylmethyl)amino}carbonyl; B is valyl, tert-butylglycyl, isoleucyl, threonyl or asparaginyl; R1 is hydrogen or fluorine; R2 is 1,1-dimethylethy1; and Y is phenyl, benzyl, phenoxy, 2-pyrimidinyloxy, (2,6-dimethyl-4-pyrimidinyl)oxy, 2-15 pyridinylmethoxy, 3-pyridinylmethoxy, 4-pyridin-ylmethoxy, phenylthio, phenylsulfinyl, phenylsulfonyl, 2-pyridinylthio, 3-pyridinylthio, 4-pyridinylthio, 2-pyrimidinylthio (4,6-dimethyl-2-pyrimidinyl)thio, (2-pyridinylmethyl)thio, (3-20 pyridinylmethyl)thio or 4-(pyridinylmethyl)thio; or a therapeutically acceptable acid addition salt thereof. Another most preferred group of compounds is 25 represented ,y formula 1 wherein X is (2- methylphenoxy)acetyl, (2,4-dimethylphenoxy)acetyl, (2,6-dimethylphenoxy)acetyl or . 2,4,6-dimethyl-phenoxy)acetyl; B is absent; R1 is hydrogen; and R2 and Y are as defined in the last instance; or a 30 therapeutically acceptable acid addition salt thereof. Preferably, with reference to the compounds of formula 1 in which B is the divalent radical 25 12 67 WO 93/18003 PCT/CA93/00096 —NHCHR5C(O)the asymmetric carbon atom bearing R5 has the (S) configuration. Included within the scope of this invention is 5 a pharmaceutical composition for treating HIV infections in a human comprising a compound of formula 1, or a therapeutically acceptable salt thereof, and a pharmaceutically acceptable carrier. 10 The scope of the invention includes as well a method for treating HIV infections in a human comprising administering thereto an effective amount of the compound of formula 1, or a therapeutically acceptable salt thereof. 15 Also included within the scope is a method for protecting human cells against HIV pathogenesis comprising treating said cells with an anti-HIV effective amount of a compound of formula 1, or a 20 therapeutically acceptable salt thereof. Processes for preparing the . compounds of formula 1 are described hereinafter. 25 Details of the Invention GENERA In general, the abbreviations used herein for designating the amino acids and the protective 30 groups are based on recommendations of the IUPAC-IUB Commission of Biochemical Nomenclature, see European Journal of Biochemistry 138. 9 (1984). For instance, Val, lie, Thr, Asn, and Leu represent the residues of L-valine, L-isoleucine, L-threonine, L-35 asparagine and L-leucine, respectively. WO 93/18003 10 2 5 12 6 7 PCT/CA93/0000' The term "lower alkyl" as used herein, either alone or in combination with a radical, means straight chain alkyl radicals cofttaining one to six carbon atoms and branched chain alkyl radicals 5 containing three to four carbon atoms and includes methyl, ethyl, propyl, butyl, hexyl, 1-methylethyl, 1-methylpropyl, 2-methylpropyl and 1,1-dimethyl-ethyl. 10 The term "lower cycloalkyl" as used herein, either alone or in combination with a radical, means saturated cyclic hydrocarbon radical containing from three to six carbon atoms and includes cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. 15 The term "lower alkoxy" as used herein means straight chain alkoxy radical containing one to six carbon atoms and branched chain alkoxy radicals containing three to four carbon atoms and includes 20 methoxy, ethoxy, propoxy, hexoxy, l-methylethoxyf butoxy and 1,1-dimethylethoxy. The latter radical is known commonly as tertiary-butyloxy. The term "halo" as used herein means a halo 25 radical selected from bromo, chloro, fluoro or iodo. The term "residue" with reference to an amino acid means a radical derived from the corresponding a-amino acid by eliminating the hydroxyl of the 30 carboxy group and one hydrogen of the a-amino group. The term "tert-butylglycyl" represents the amino acid residue of 2 (S) -amino-3, 3-dimethylbutanoic acid and the term "N4- WO 93/18003 11 25 12 67 PCI7CA93/00096 methylasparaginyl" represents the amino acid residue of 2(S)-amino-4-methylamino-4-oxobutanoic acid. The term "Het" as used herein means a 5 monovalent radical derived by removal of a hydrogen from a five- or six-membered saturated or unsaturated heterocycle containing from one to two heteroatoms selected from nitrogen, oxygen and sulfur. Optionally', the heterocycle may bear one or 10 two substituents; for example, lower alkyl, lower alkoxy, halo, amino or lower alkylamino. Examples of suitable heterocylces and optionally substituted heterocycles include pyrrolidine, tetrahydrofuran, thiazolidine, pyrrole, 1H-imidazole, 1-methyl-lff- 15 imidazole, isoxazole, thiazole, 2-methylthiazole, 2-aminothiazole, piperidine, 1,4-dioxane, 4- morpholine, pyridine, 2-methylpyridine, pyrimidine, 4-methylpyrimidine and 2,4-dimethylpyrimidine. 20 The term "phannaceutically acceptable carrier" as used herein means a non-toxic, generally inert vehicle for the active ingredient, which does not adversely affect the ingredient. 25 The term "effective amount" as used herein means a predetermined amount of the compound of this invention sufficient to be effective against HIV in vivo. 30 PROCESS In general, the compounds of formula 1 are prepared by known methods using reaction conditions which are known to be suitable for the reactants. 35 Description of the methods are found in standard 2 5 12 6 7 WO 93/18003 PCT/CA93/0009' 12 textbooks such as "Annual Reports In Organic Synthesis - 1990", X. Turnbull et al., Eds, Academic Press, Inc., San Diego, CA, USA, 1990 (and the preceding annual reports), "Vogel's Textbook Of 5 Practical Organic Chemistry", B.S. Furniss et al., Eds, Longman Group Limited, Essex, UK, 1986, and "The Peptides: Analysis, Synthesis, Biology", E. Grass et al., Eds, Academic Press, New York, NY, USA, 1979-1987, Volumes 1 to 9. 10 More particularly, the compounds of formula 1 can be prepared by a process comprising: (a) reacting an epoxide of formula 2 13 X'NHy</ 2. 20 wherein X and R1 are as defined herein with a piperidinecarboxamide of formula 3 c(o>nhr2 1 25 wherein R2 and Y are as defined herein to obtain the corresponding compound of formula 1 wherein X, R1, R2 and Y are as defined herein and B is absent; or (b) reacting a compound of formula 4 30 WO 93/18003 13 25 12 67 PCT/ C A93/00096 C(O) NHR2 .■M L wherein R1, R2 and Y are as defined herein with a reactive derivative of the carboxylic acid X-OH 10 wherein X is R3C(0) or R3A0CH2C(0) as defined herein to obtain the corresponding compound of formula 1 wherein X is R3C(0) or R3*0CH2C(0) as defined herein, R1, R2 and Y are as defined herein and B is absent; or 15 (c) coupling the compound of formula 4 wherein R1, R2 and Y are as defined herein with an a-amino acid of the formula X-NHCHR5COOH wherein X and R5 are as defined herein in the presence of a coupling agent to obtain the corresponding compound of formula 1 20 wherein X, R1, R2 and Y are as defined herein and B is the divalent radical -NHCHR5C(0)- wherein R5 is as defined herein; or (d) reacting a compound of formula 5 25 H2NCHR5C(0)NH C(0)NHR2 30 wherein R1, R2, R5 and Y are as defined herein with a reactive derivative of the carboxylic acid X-OH wherein X is R3C(0) or R3A0CH2C(0) as defined herein 35 to obtain the corresponding compound of formula 1 WO 93/18003 14 25 12 67 PCT/CA.93/000? wherein X is R3C(0) or R3AOCH2C(0) as defined herein, R1, R2 and Y are as defined herein and B is the divalent radical -HHCHR5C(0)- wherein R5 is as defined herein; and 5 (e) if desired, transforming the compound of formula 1, as obtained in the preceding sections (a), (b), (c) or (d), into a corresponding therapeutically acceptable acid addition salt. 10 It. should be noted that the species of compounds of formula 1 in which X is a commonly used N-protective group, e.g. Boc, Z, Fmoc or p-methoxybenzyloxycarbonyl, are obtained most readily 15 and conveniently by processes (a) and (c). The ready accessibility of this species renders them useful as intermediates for a preferred route, via respective processes (b) and (d), to produce the respective compounds of formula 1 in which X is 20 other than a commonly used N-protective group. As intermediates, therefore, the compounds of formula 1 of this species are deprotected (i.e. the protective group is removed), and the resulting N-terminal free amines are used as the respective compounds of 25 formula 4 or formula 5 according to processes (b) and (d), depending on whether B is absent or present, for the ultimate preparation of the compounds of formula 1 in which X is other than a commonly used N-protective group, e.g. 2-30 pyridinylmethoxycarbonyl or 2-quinolinylcarbonyl. More explicitly, according to the preceding process (a), the compounds of formula 1 in which B is absent can be prepared by an N-alkylation 35 reaction involving the addition of the epoxide 2 to 25 12 67 WO 93/18003 PCI7CA93/00096 15 the piperidinecarboxamide 3. The reaction can be effected conveniently by bringing the two reactants into contact in an inert solvent, e.g. ethanol, tetrahydrofuran or dimethylformamide, at 5 temperatures ranging from 20* to 110*C, The reaction time is dependent on temperature and the nature of the reactants but generally ranges from two to 24 hours. 10 According to process (b), the compounds of formula 1 in which B is absent are obtained by reacting the corresponding compound of formula 4 with a reactive derivative of the carboxylic acid X-OH. Suitable reactive derivatives are the acylating 15 agents capable of providing the appropriate acyl radical X-CO and include the corresponding acid halides, preferably the chlorides or bromides, active esters, anhydrides or mixed anhydrides. The reaction is performed according to known methods and 20 conditions for accomplishing the reaction including the means to impart the desired selectivity to the reaction by choosing appropriate ratios of the v reactants or by temporarily providing known protecting groups, if required, for any other 25 reactive group competing with the intended reactive groups. Generally, the reaction is performed in an inert solvent, e.g. tetrahydrofuran, dimethyl-formamide or methylene dichloride, at a temperature between 0# and 50°C and a reaction time ranging from 30 15 minutes to 24 hours. According to process (c), the compounds of formula 1 in wtiich B is the divalent radical —NHCHR5C (O) - whereiin R5 is as defined herein can be 35 obtained by coupling the compound of formula 4 with 2512 67 WO 93/18003 PCT/CA93/0009'r 16 an a-amino acid of formula X-NHCHR5COOH in the presence of a coupling agent. The use of coupling agents to promote the dehydrative coupling of a free carboxyl of one reactant with a free amino group of 5 the other reactant is well known; for example, see "The Peptides: Analysis, Synthesis, Biology", Volumes 1 to 8, noted hereinbefore. Examples of suitable coupling agents are 1, l'-carbonyl-diimidazole or N,N/-dicyclohexyl-carbodiimide. 10 Other examples are 1-hydroxybenzotriazole in the presence of N,N^-dicyclohexylcarbodiimide or N-ethyl-N/-[ (3-dimethyl-amino) propyl ]carbodiimide. A very practical and useful coupling agent is the commercially available (benzotriazol-l-yloxy)tris-15 (diir.ethylamino)phosphonium hexaf luorophosphate, either by itself or in the presence of 1-hydroxybenzotriazole. Still another very practical and useful coupling agent is the commercially available 2-(lH-benzotriazol-l-yl)-N, N, N', N'-20 tetramethyluronium tetrafluoroborate. The co pling reaction is conducted in an inert solvent, e.g. methylene dichloride, acetonitrile or dimethylformamide. An excess of an organic amine, 25 e.g. diisopropylethyl amine or N-me\.nylmorpholine, is added to maintain tha reaction mixture at a pH of about eight. The reaction temperature usually range's from -20° to about 30*C and reaction time from 15 minutes to eight hours. 30 With reference to process (d), this process is performed in the same manner as described hereinabove for process (b), the only exception being in the use of the compound of formula 5 WO 93/18003 17 2512 67 PCT/CA93/00096 instead of the compound of formula 4 as a starting material. The epoxides of formula 2 used as starting 5 materials for the process (a) are either known or can be prepared by known methods. More specifically the epoxides of formula 2 are either described by B.K. Handa et al., European patent application 346,847, published December 20, 1989, or they can be 10 made by methods described in the patent application. The other starting materials for the processes, i.e. the piperidinecarboxamides of formula 3, and the compounds of formulae 4 and 5, are novel and 15 therefore are an object of this invention. Suitable processes for the preparation of the compounds of formulae 4 and 5 have rieen noted hereinbefore. The third species of novel intermediates, the piperidinecarboxamides of formula 3, can be prepared 20 by choosing the appropriate 4-substituted piperi-dine, many of which are known or can be prepared by analogous methods used for preparing the known 4-substituted piperidines, and subjecting the chosen piperidine to known methods for introducing a 25 carboxamide function at position 2 of a piperidine. A convenient method for effecting the latter transformation is illustrated hereinafter in the examples. 30 The compound of formula 1 of this invention can be obtained in the form of a therapeutically acceptable acid addition salt. Examples of such salts are those with organic acids, e.g. acetic, lactic, succinic, benzoic, salicylic, 35 methanesulfonic or p-toluenesulfonic acid, as well WO 93/18003 18 25 12 67 PCT/CA93/0009' as polymeric acids such as tannic acid or carboxymethyl cellulose, and also salts with inorganic acids such as hydrohalic acids, e.g. hydrochloric acid, or sulfuric acid, or phosphoric 5 acid. If desired, a particular acid addition salt is converted into another acid addition salt, such as a non-toxic, pharmaceutically acceptable salt, by treatment with the appropriate ion exchange resin in the manner described by R.A. Boissonnas et al., 10 Helv. Chim. Acta, 13., 1849 (1960). 15 In general, the therapeutically acceptable salts of the peptides of formula 1 are biologically fully equivalent to the peptides themselves. BIOLOGICAL ASPECTS The HIV protease inhibiting properties and the cell protective effect against HIV pathogenesis of 20 the compounds of formula 1, or a therapeutically acceptable salt thereof, can be demonstrated by biochemical, microbiological and biological procedures. 25 A particular useful procedure for demonstrating the HIV protease inhibiting properties of the compounds of formula 1 or their therapeutically acceptable salts is the "Recombinant HIV Protease HPLC Assay". The procedure is based on the capacity 30 of the test compound to inhibit enzymatic cleavage by HIV protease of a decapeptide (the substrate) having an amino acid sequence which includes a known HIV protease cleavage site of a HIV polyprotein; see H.G. Krausslich et al., Proc. Natl. Acad. Sci. USA, 35 jJ6., 807 (1989). Details of this assay together with WO 93/18003 19 25 12 67 PCT/CA93/00096 the results obtained for exemplified compounds of formula 1 are described in the examples hereinafter. The capacity of the compounds of formula 1 or 5 their therapeutically acceptable salts to protect cells against HIV infection can be demonstrated by microbiological procedures for evaluating the inhibitory effect of a test compound on the cytopathogenicity of HIV in human T4 cell lines. 10 Typical of such procedures are those described by S. Harada and N. Yamamoto, Jpn. J. Cancer Res. (Gann), 76. 432 (1985), and S. Harada et al., Science, 229. 563 (1985). An assay based on the latter procedures is described in the examples hereinafter. 15 When a compound of this invention, or a therapeutically acceptable salt thereof, is used to combat HIV infections in a human, the peptide can be administered orally, topically or parenterally, in a 20 ehicle comprising one or more pharmaceutical ly acceptable carriers, the proportion of which is determined by the solubility and chemical nature of the compound, the chosen route of administration and standard biological practice. For oral administra-25 tion, the compound or a therapeutically acceptable sail, thereof can be formulated in unit dosage forms such as capsules or tablets each containing a predetermined amount of the active ingredient, ranging from about 5 to 150 mg, in a pharmaceu-30 tically acceptable carrier. For topical administration, the compound can be formulated in a pharmaceutically acceptable vehicle containing 0.01 to 2 percent, preferably 0.05 to 1 percent, of the active agent. Such formulations can be in the form 35 of a cream, lotion, sublingual tablet, or preferably 25 12 67 WO 93/18003 PCT/CA93/000?' 20 a transdermal patch or buccal patch. For parenteral administration, the compound of formula 1 is administered by either intravenous, subcutaneous or intramuscular injection, in compositions with 5 pharmaceutical^ acceptable vehicles or carriers. For administration by injection, it is preferred to use the compound in solution in a sterile aqueous vehicle which may also contain other solutes such as buffers or preservatives as well as sufficient 10 quantities of pharmaceutically acceptable salts or of glucose to make the solution isotonic. Suitable vehicles or carriers for the above noted formulations can be found in standard 15 pharmaceutical texts, e.g in "Remington's Pharmaceutical Sciences", 18th ed., Mack Publishing Company, Easton, Penn., 1990. The dosage of the compound will vary with the 20 form of administration and the particular active agent chosen. Furthermore, it will vary with the particular host under treatment. Generally, treatment is initiated with small dosages substantially less than the optimum dose of the 25 peptide. Thereafter, the dosage is increased by small increments until the optimum effect under the circumstances is reached. In general, the compound is most desirably administered at a concentration level that will generally afford antivirally 30 effective results without causing any harmful or deleterious side effects. For oral administration, the compound or a therapeutically acceptable salt is administered in 35 the range of 0.5 to 15 mg per kilogram of body 25 12 67 WO 93/18003 PCT/CA93/00096 21 weight per day, with a preferred range of 0.5 to 5 mg per kilogram. With reference to systemic administration, the compound of formula 1 is administered at a dosage of 1 ng to 100 jxg per 5 kilogram of body weight per day, although the aforementioned variations will occur. Although the formulations disclosed hereinabove are effective and relatively safe medications for 10 treating HIV infections, the possible concurrent administration of these formulations with other antiviral medications or agents to obtain beneficial results is not excluded. Such other antiviral medications or agents include soluble CD4, 15 zidovudine, didanosine, zalcitabine, trisodium phosphonoformate, ribavarin, acyclovir or antiviral interferons (e.g. a-interferon or interleukin-2). The following examples illustrate further this 20 invention. Solution percentages or ratios express a volume to volume relationship, unless stated otherwise. Temperatures are given in degrees Celsius. Proton nuclear magnetic resonance (NMR) spectra were recorded on a Bruker 200 MHz 25 spectrometer; the chemical shifts (6) are reported in parts per million. Abbreviations used in the examples include Bocs tert-butyloxycarbonyl; BOP: (benzotri-azol-l-yloxy)tris-(dimethylamino)-phospho-nium hexaf luorophosphate; Bu*1: tert-butyl; Bzl: 30 benzyl; DIEA: diisopropylethylamine; DMF: dimethylformamide; HEPES: N-2-hydroxyethyl- piperazine-N/-2-ethanesulfonic acid; Et20: diethyl ether; EtOAc: ethyl acetate; EtOH: ethanol; HPLC: high performance liquid chromatography; MeOH: 25 12 67 WO 93/18003 PCT/CAQS/OOO1* 22 methanol; Ph: phenyl; THF: tetrahydrofuran; Z: benzyloxycarbonyl. Example 1 5 Preparation of l-(tert-Butyloxycarbonyl)-4-(phenylthio)piperidine A solution of l-(tert-butyloxycarbonyl)-4-10 piperidinol (3.0 g, 14.9 mmol) in THF (30 mL) was cooled to 0*. Triethylamine (3.2 mL, 1.5 equiv.) was added to the solution, followed by the gradual addition of methylsulfonyl chloride (1.26 mL, 1.1 equiv.). The reaction mixture was stirred at 0* for 15 2 h. Et20 (30 mL) and H20 (20 mL) were added and the mixture was stirred at 0* for an additional 30 min. The mixture was diluted with Et20 (200 mL). The organic layer was washed successively with H20, 10% aqueous citric acid, a saturated aqueous solution of 20 NaHC03 (2X) and brine. The organic layer was dried (MgS04) and concentrated under reduced pressure to give l-{tert-butyloxycarbonyl)-4-piperidinol methyl-sulfonate ester (4.0g, 96%) as a yellowish solid. XH NMR (CDC13) 6 4.90 (m, 1H), 3.72 (ddd, J = 4.3, 25 6 . 5, 13.5Hz, 2H), 3.32 (ddd, J » 4.3, 8.1, 13.5Hz, 2H), 3.05 (s, 3H), 1.47 (s, 9H). The latter methylsulfonate was used without further purification to prepare the title compound 30 as follows: Thiophenol (1.84 mL, 17.9 mmol) was added slowly to a suspension of NaH (334 mg, 14.3 mmol) in DMF (8 mL) at 0". The mixture was stirred for 20 min. A solution of the latter methylsulfonate (2.0 g, 7.17 mmol) in DMF (6 mL) was 35 added and the resultant mixture was stirred at room WO 93/18003 23 25 12 67 PCT/CA93/00096 temperature (20-22*) for 18 h. The mixture was diluted with Et20 and the organic phase was washed successively with 1 M aqueous NaOH (3X) and brine. The organic layer was dried (MgS04) and concentrated 5 to dryness under reduced pressure. The residue was purified by flash chromatography (Si02, eluents EtOAc-hexane, 1:9 and then 1:6) to give the title compound (1.82 g, 86%) as an oil which solidified on standing. *H NMR (CDC13) 6 7.48-7.2 (2m, 2H + 3H), 10 3.97 (m, 2H), 3.22 (m, 1H), 2.80 (ddd, J = 3.8, 10.5, 13.5Hz, 2H), 1.47 (s, 9H). FAB mass spectrum, m/zi 294 (M + H)+. 15 Example 2 Preparation of d, l-cis-N-tert-Butyl-l-(tert-butyloxycarbonyl)-4-(phenylthio)piperidine-2-carboxamide 20 A solution of the title compound of example 1 (3.57 g, 12.2 mmol) in Et20 (60 mL) was cooled to -78*. N,N,N/,N/-Tetramethylenediamine (4.6 mL, 2.5 equiv.) was added to the cooled solution, followed by the gradual addition of 1.3 M sec-butyllithium in 25 cyclohexane (12.0 mL, 1.3 equiv.). The mixture was stirred for 3.5 h at -78*. Thereafter, tert-butylisocyanate (2.1 mL, 1.5 equiv.) was added rapidly and the reaction mixture was stirred for 40 min at -78°. The reaction mixture was quenched with 30 10% aqueous citric acid and then allowed to warm to room temperature. The organic phase was separated and the aqueous phase was extracted with Et20. The combined organic phases were washed with a saturated aqueous solution of NaHC03 and brine, dried (MgS04) 35 and evaporated under reduced pressure. The residue 25 1 2 WO 93/18003 PCT/CA93/0000' 24 10 was purified by flash chromatography (Si02, eluent: hexane-EtOAc, 6:1 and then 4:1) to give the title compound (4.34g, 90%) as a colorless oil which solidified on standing. JH NMR (CDC13) 6 7.42 (m, 2H), 7.28 (m, 3H), 5.85 (broad s, 1H), 4.43 (dd, J = 4.0, 7.0Hz, 1H), 3.92 (ddd, J = 3.5, 5.0, 13.5Hz, 1H), 3.49 (m, 1H), 3.32 (ddd, J = 4.0, 11.5, 13.5Hz, 1H), 1.48 (s, 9H), 1.39 (s, 9H). FAB mass spectrum, m/z: 393 (M + H)+. Example 3 Preparation of d, l-cis-N-tert-Butyl-l-(tert-butyloxycarbonyl)-4-(2-pyridinyloxy)piperidine-2-15 carboxamide A solution of l-(tert-butyloxycarbonyl)-4-piperidinol (5.2 g, 25.9 mmol), tert-butyldi-methylsilyl chloride (4.07 g, 1.05 equiv.) and 20 imidazole (2.7 g, 1.5 equiv.) in DMF (20 mL) was stirred for 16 h. After dilution with Et20, the solution was washed successively with H20 (2X), 10% aqueous citric acid, a saturated aqueous solution of NaHC03 and brine. The organic layer was dried 25 (MgS04) and concentrated to dryness. The residue was purified by HPLC using a WATERS ® LC-500 preparative chromatography apparatus [2 Si02 columns: hexane-EtOAc (19:1), Millipore Corporation, Milford, MA, USA] to give l-(tert-butyloxycarbonyl)-4-(tert-30 butyldimethylsiloxy)piperidine (7.54 g, 92%). XH NMR (CDC13) 6 3.87 (m, 1H) , 3.61 (ddd, J = 3.5, 7.5, 13.0Hz, 2H), 3.24 (ddd, J = 3.7, 8.0, 13.0Hz, 2H), 1.48 (s, 9H), 0.88 (s, 9H) , "*.07 (s, 6H). WO 93/18003 25 25 12 67 PCT/CA93/00096 Thereafter, by following the procedure of example 2 but replacing 1-(tert-butyloxycarbonyl)-4-(phenylthio)piperidine with the aforementioned 1-(tert-butyloxycarbonyl)-4-(tert-butyldimethylsil-5 oxy)piperidine, d,l-cis-N-tert-butyl-l-(tert-butyl oxycarbonyl )-4-(tert-butyldimethylsiloxy)piperidine-2-carboxamide was obtained. XH NMR (CDC13) 6 5.70 (s, 1H), 4.47 (dd, J = 2.7, 8.0Hz, 1H), 4.07 (m, 1H), 3.83 (m, 1H), 3.22 (ddd, J = 5.4, 10.5, 10 13.5Hz), 1.48 (s, 9H), 1.35 (s, 9H), 0.88 (s, 9H), 0.1 and 0.08 (2s, 6H). To a solution of the latter compound (700 mg, 1.69 mmol) in THF (10 mL), a solution of 1 M 15 tetrabutylammonium fluoride in THF (2.15 mL, 1.25 equiv.) was added. The reaction mixture was stirred at room temperature for 30 min and then diluted with Et20. The resultant mixture was washed with HaO (2X) and brine (IX). The organic layer was dried (MgS04) 20 and concentrated to dryness under reduced pressure. The residue was purified by flash chromatography (SiOz, eluent: hexane-EtOAc, 1:1) to give the carboxamide, d,1-cis-N-tert-butyl-l-(tert-butyloxycarbonyl ) -4-hydroxypiperidine-2-carboxamide (386 mg, 25 76%), as a white solid. FAB mass spectrum, m/z: 301 (M + H) + . Diethyl azodicarboxylate (173 pL, 1.5 equiv.) was added to a cold solution (0*) of the latter 30 carboxamide (220 mg, 0.73 mmol), 4-nitrobenzoic acid (244 mg, 2.0 equiv.) and triphenylphosphine (288 mg, 1.5 equiv.) in benzene-THF (5:1, 13 mL). The reaction mixture was stirred at 0# for 30 min and then at room temperature for 3 h. The solvent was 35 removed under reduced pressure. The residue was 25 12 67 WO 93/18003 PCT/CA93/000<V' 26 purified by flash chromatography (Si02, eluent: hexane-EtOAC, 4:1) to give d,1-trans-N-tert-butyl-l-(butyloxycarbonyl)-4-(4-nitrobenzoyloxy)-2-carboxa-mide (280 mg) containing about 25 to 30% of a 5 contaminant (an elimination product). The total product was used for the next step without further purif ication. A mixture of the latter product (404 mg, 0.9 10 mmol) and K2C03 (28 mg, 0.2 equiv.) in MeOH (9 mL) was stirred at room temperature for 18h. The solvent was removed under reduced pressure. The residue was dissolved in CHC13 and the resulting solution was washed with H20, dried (MgS04) and 15 concentrated to dryness under reduced pressure. The residue was puridied by flash chromatography (Si02, eluent: hexane-EtOAc,1:1 and then 1:2) to give d,1-trans-tert-butyl-l-(N-tert-butyloxycarbonyl) -4-hydroxypiperidine-2-carboxamide (194 mg, 71%). 20 A solution of the latter compound (145 mg, 0.48 mmol), 2-hydroxypyridine (68 mg, 1.5 equiv.) and triphenylphosphine (187 mg, 1.5 equiv.) in benzene-THF (5:1, 12 mL) was cooled to 0*. Diethyl 25 azodicarboxylate (114 nL, 1.5 equiv.) was added to the solution. The mixture was stirred for 1.5 h at 0* and then at room temperature for 30 min. The solvent was removed under reduced pressure. The residue was purified by flash chromatography (SiOz, 30 eluent: hexane-EtOAc, 2:1) to give the title compound of this example (70 mg, 38%). NMR (CDCl3) 6 8.12, 7.43, 6.85 and 6.62 (4m, 4H), 5.72 (s, 1H), 5.39 (m, 1H), 4.63 (m, 1H), 4.05 (m, 1H), 3.29 (m, 1H), 1.48 (s, 9H), 1.36 (s, 9H). 35 WO 93/18003 27 25 12 67 PCT/CA93/00096 Preparation of d,l-cis-N-tert-Butyl-l-(tert-butyloxycarbonyl )-4-(phenylsulfonyl)piperidine-2-5 carboxamide A mixture of the title compound of example 2 (1.68 gf 4.28 iranol) and 3-chloroperoxybenzoic acid (2.2 g, 12.83 iranol) in CH2C12 (2 0 mL) was stirred at 10 room temperature for 18 h. The reaction mixture was quenched with a 10% aqueous solution of sodium sulfite and then diluted with EtOAc. The organic layer was separated, washed successively with a saturated aqueous solution of NaHC03, H20 and brine, 15 dried (MgS04) and concentrated under reduced pressure. The solid residue was triturated with hexane-EtOAc (18 mL/12 mL) and then collected on a filter to give the title compound (1.57 g, 86%) as a white solid. !h NMR(CDC13) 6 7.90 (m, 2H), 7.75-7.55 20 (m, 3H), 5.95 (s, 1H), 4.07 (dd, J = 8.0, 9.5Hz, 1H), 3.88 (dt, J = 5.4, 13.5Hz, 1H) , 3.32-3.05 (m, 2H), 1.45 (s, 9H), i.35 (s, 9H). FAB mass spectrum, m/z: 425 (M + H)+. 25 By the following the procedure of this example, but using only one molar equivalent of 3-chloroperoxybenzoic acid, d,1-ois-N-tert-butyl-l-(tert-butyloxycarbonyl)~4-(phenylsulfinyl)piperidi-ne-2-carboxamide was obtained. 30 EXOTPJ-e 5 Preparation of N-tert-Butyl-l-[3(S)-(tert-butyloxycarbonyl amino )-2(R)-hydroxy-4-phenylbutyl]-35 4(R)-(phenylthio)piperidine-2(S)-carboxamide WO 93/18003 28 2 5 12 6 7 PCT/CA93/OOOr (formula 1; X = Boc, B is absent, R1 = H, R2 = C(CH3)3 and Y = PhS) (a) d, 1-cis-N-tert-Butyl-4-(phenylthio)piperidine-2-5 carboxamide, a piperidinecarboxamide of formula 3 in which R2 is C(CH3)3 and Y is PhS, was prepared as follows: A solution of the corresponding Boc-protected derivative of the piperidinecarboxamide (3.04 g, 7.76 mmol), i.e. the title compound of 10 example 2, in 6 N HCl/dioxane was stirred at room temperature for 20 min and then concentrated to dryness under reduced pressure to give the desired piperidinecarboxamide of formula 3 wherein R2 is C(CH3)3 and Y is PhS. 15 (b) The title compound of this example was prepared as follows: A mixture of the latter piperidinecarboxamide in EtOAc (50 mL) and 2N aqueous NaOH (20 mL) was stirred at room temperature for 15 min. The organic layer was separated, washed 20 with a minimum amount of H20 and brine, dried (MgS04) and evaporated to dryness under reduced pressure. The resulting oil was dried under high vacuum for about 45 min. The oil was mixed with the epoxide of formula 2., 3(S)-(tert-butyloxycarbonylamino)—l,2(R) — 25 epoxy-4-phenylbutane (2.45 g, 9.36 mmol), see B.K. Handa et al., supra, and absolute EtOH (40 mL). The mixture was heated at reflux for 18 h. After an additional amount of the epoxide (600 mg) was added, the mixture was heated at reflux for 4 h. The 30 mixture was concentrated to dryness under reduced pressure. The crude product was purified by HPLC using a WATERS® LC-500 preparative chromatography apparatus [2 Si02 columns: hexane-EtOAc (6:4), Millipore Corporation, Milford, MA, USA] to give the 35 title compound as a white foam [1.46g, 34% for the 25 12 67 WO 93/18003 PCT/CA93/00096 29 desired (more polar) isomer]. FAB mass spectrum, m/zi 556 (M + H)+ . The procedure of example 5 may be followed to 5 prepare other compounds of formula 1 in which B is absent and X, R1, R2 and Y are as defined herein. For example, by replacing 3(S)-(tert-butyloxy-carbonylamino)-l,2(R)-epoxy-4-phenylbutane with an equivalent amount of 3(S)-(tert-butyloxycarbonyl-10 amino)-l,2(R)-epoxy-4-(4-fluorophenyl)butane, N- tert-buty1-1-{3(S)-{(benzyloxycarbony1)amino}-2(R)-hydroxy-4-(4-fluorophenyl)butyl} -4 (R) - (phenylthio)-piperidine-2(S)-carboxamide [FAB mass spectrum, m/zi 608 (M + H)+] is obtained. 15 Still other examples of such compounds are listed in Table I. In each of these examples an equivalent amount of the epoxide of formula 2 listed therein is used instead of the epoxide of formula 2 20 described in example 5 and an equivalent amount of the piperidinecarboxamide of formula 3 listed therein instead of the piperidinecarboxamide of formula 3 described in example 5. 25 30 35 25 12 67 PCT/CA93/0000" 30 TABLE I Entry No. Epoxide of Formula 2 Piperidine- I carboxamide of E Formula 3 'roducfc: N-fcert-3utyl-l-{3(S)-[ (XJ-amino}-2(R)-aydroxy-4-phenyl-auty1}-F-piperi-iine-2(S)-carboxamide X R1 R2 Y X//Y 1 z H Bu^ Ph benzyloxycarbo-ny1//4(R)-phenyl (558)* 2 z H But Bzl benzyloxycarbo-nyl//4(R)-benzyl (572) 3 z H But S02Ph benzyloxycarbo-nyl//4(R)-(phe-nylsulfonyl) (622) 4 z H But SPh benzyloxycarbo-nyl//4(R)-(phenylthio) (590) 5 z H But OPh benzyloxycarbo-nyl//4(R)-phenoxy (574) 6 z H But 0- (2-pyridyl) benzyloxycarbo-nyl//4(R)-(2-pyridinyloxy) (575) 7 z H But cyclo-hexyl benzyloxycarbo-nyl//4(R)-cyclo-hexyl(564) 31 25 12 67 PCT/CA93/00096 TABLE I (continued) Entry Mo. Epoxide of Formula 2 Piperidine- I carboxamide of E Formula 3 ■ •roducts N-terfc-iutyl-l~{3(S)-((X)-amino}-2(R)-aydroxy-4-phenyl-3utyl>-3f~piperi-dfine-2 (S ) -carboxamide X R1 R2 Y X//Y 8 z H But S-(2-pyridinyl ) benzyloxycarbo-nyl//4(R)-(2-pyridinylthio) (591) 9 z H But S-(4-py-ridinyl) benzyloxycarbo-nyl//4(R)-(4-pyridinylthio) (591) 10 z H But S-(2-py-rimidin- yi) benzyloxycarbo-nyl//4(R)-(2-pyrimidinylthio) (592) 11 z H But S-(4,6-dimeth-yl-2-py-rimidin- yi) benzyloxycarbo-nyl//4(R)-(4,6-dimethyl-2-pyrimidinylthio) (620) 12 z H But SCH2Ph benz vloxyc arbo-nyl//4(R)-benzylthio (604) 13 z H Bufc S-(4-py-ridinyl-methyl) benzyloxycarbo-nyl//4(R)-{(4-pyr'idinylmeth-yl)thio} (605) 32 25 12 67 PCT/CA93/0000' TABLE I (continued) Entry NO. Epoxide of Formula 2 Piperidine- I carboxamide of e Formula 3 »roduct: N-fcert-Jutyl-l-{3(S)-; (XJ-amino}-2(R)-iydroxy-4-phenyl-auty1>-r-piperi-Jine-2(S)-car-soxamide X r1 R2 Y X//Y 14 z H Bufc S-(3-py-ridinyl-methyl) benzyloxycarbo-nyl//4(R)-{(3-pyridinylmeth-yl)thio> (60^) 15 Boc H But O-(2-py-ridinyl-methyl) tert-butyloxj carbonyl/ / 4 (R) -(2-pyridinylmethoxy) (555) 16 Boc H But S-(2-pyridinylmethyl ) tert-butyloxy-carbony1/ / 4 (R) -{(2-pyridinylmethyl) thio} (571) 17 boc H But 0-(2-py-rii^idin- yi) tert-butyloxycarbonyl //4(R) -(2-pyrimidinyl-oxy) (542) 18 Boc H But 0-(4,6-dimeth-yl-2-py-rimidin- yi) tert-butyloxy-carbonyl//4(R)-{(4,6-dimethyl-2-pyrimidin-yl)oxy} (570) 19 boc H But 0- (4-methyl-2-pyri-midinyl) tert-butyloxy-carbonyl//4(R)-{(4-methyl-2-py-rimidinyl)oxy} (556) 25 12 67 PCT/CA93/00096 TABLE I (continued) Entry No. Epoxide of Formula 2 Piperidinecarboxamide of Formula 3 Product: N-tari-| Butyl-1-{3(S>-{(x;-amino}-2(R)-bydroxy-4-phenyl-Duty1}-Y-piperi-dine-2(S)-carboxamide X Rl R2 Y X//Y 20 Boc H Bu* 0-(2,6- dimethyl 4-pyri-midinyl) tert-butyloxy-carbonyl//4(R)-{ (2,6-dimethyl-4-pyrimidin-yl)oxy> (570) 21 BOC H But S-(2,6-dimethyl 4-pyri-midinyl) tert-butyloxy-carbony1//4(R)-{{2,6-dimethyl-4-pyrimidiny 1)-thio) (586) 22 Boc H But S- (4-methyl-2-pyri-midinyl) tert-butyloxy-carbonyl//4(R)-{(4-methyl-2-py-rimidinyl)thio} (572) The number in parenthesis following the designation of the product for each entry is the found (M + H)+ from the FAB mass spectrum of the product. 251267 WO 93/18003 PCT/CA93/0000' 34 Example 6 Two procedures for the preparation of compounds of formula 1 in which B is the divalent radical 5 -NHCHR5C(0)- wherein R5 is as defined herein are provided in this example. The first exemplified procedure, example 6A, is preferred for compounds of formula 1 in which B is other than Asn, and the second exemplified procedure, example 6B, is 10 preferred for compounds of formula 1 in which B is Asn. Preparation of N-tert-Butyl-l-{3(S)-{{N-(tert-butyloxycarbonyl )valyl}amino}-2(R)-hydroxy-4-phenyl-15 butyl>-4(R)-(phenylthio)piperidine-2(S)-carboxamide (formula 1; X = Boc, B = Val, R1 = H, R2 = C(CH3)3 and y = phS) A solution of the compound of formula 1 wherein 20 X is Boc, B is absent, R1 = H, R2 = C(CH3)3 and Y = PhS (1.14 g, 2.04 mmol), i.e. the title compound of example 5, in 6 H HCl/dioxane (10 mL) was stirred at room temperature for 20 min. The solvent was removed under reduced pressure. The white solid 25 residue was triturated with Et20, collected on a filter and dried to give the corresponding deprotected amine as a hydrochloride salt (1.06 g, 98%). 30 The latter salt (341 mg, 0.645- mmol) was dissolved in CH2C12 (3.5 mL). DIEA (225 jxL, 1.29 mmol), the protected amino acid Boc-Val-OH (145 mg, 0.667 mmol) and BOP (342 mg, 0.774 mmol) were added to the solution of the salt. The reaction mixture 35 was maintained at pH 8 by periodic verification and 25 12 67 WO 93/18003 PCT/CA93/00096 35 the addition of DIEA as required while the reaction mixture was stirred at room temperature for 3.5 h. Thereafter, the reaction mixture was diluted with EtOAc, washed successively with a saturated aqueous 5 solution of NaHC03 (2X), H20 and brine. The organic layer was dried (MgS04) and concentrated under reduced pressure. The residue was purified by flash chromatography (Si02, eluent: hexane-EtOAc, 1:1) to give the title compound of section A of this example 10 as a white solid (338 mg, 80%). FAB mass spectrum, m/zt 655.3 (M + H)+. B: Preparation of N-tert-Butyl-l-{3(S)-{{N-(tert-butyloxycarbonyl)asparaginyl}amino}-2(R)-hydroxy-4-15 phenylbuty1}-4(R)-(phenylthio)piperidine-2(S)- carboxamide (formula 1; X=Boc, B=Asn, R1=H, R2=C(CH3)3 and Y *» PhS) 1-Hydroxybenzotriazole (1.97 g, 14.57 mmol) was 20 added to a cooled (0*) solution of N,N^-dicyclohexylcarbodiimide (2.4 mmol/mL in CH2C12, 6.7 mL, 16.08 mmol) and THF (45 mL). The mixture was stirred for 15 min. The protected amino acid Boc-Asn-OH (3.38 g, 14.57 mmol) and a solution of the 25 corresponding deprotected amine of the title compound of example 5 (3.30 g, 7.24 mmol) in DMF (40 mL) were added to the mixture. (Note: The deprotected amine was obtained as described in the first paragraph of example 6A, followed by 30 transforming the hydrochloride salt to its free base.) The mixture was allowed to warm slowly to room temperature and then stirred for 18 h. Thereafter, the mixture was diluted with EtCAc and H20. The organic phase was separated, washed with a 35 saturated aqueous solution of NaHC03, H20 and brine, 251267 WO 93/18003 PCT/CA93/0009' 36 dried (MgS04) and concentrated to dryness under reduced pressure. The solid residue was purified by flash chromatography (Si02/ eluent: CHCl3-MeOH, 97.5:2.5) to give the title compound of section B of 5 this example as a white solid (3.56 g, 73%). FAB mass spectrum, m/z: 670 (M + H)+. The procedures of example 6 may be followed to prepare other compounds of formula 1 in which B is 10 the divalent radical -NHCHR5C(0)- wherein R5 is as defined herein and R1, R2, X and Y are as defined herein. For example, with reference to section A of this example, by replacing the title compound of example 5 with an equivalent cimount of N-tert-butyl-15 1~{3(S)-{ (benzyloxycarbonyl)amino}-2 (R)-hydroxy-4-(4-fluorophenyl) butyl}-4 (R) - (phenylthio) piperidine-2 (S)-carboxamide, described in example 5, N-tert-butyl-1-{ 3 (S) - { {N- (benzyloxycarbonyl) valyl > amino} -2 (R) -hydr oxy-4 - (4 -f luorophenyl) butyl} -4 (R) - (phenyl -20 thio)piperidine-2(S)-carboxamide {Mass spectrum, m/zi 707 (M + H)+} is obtained. Still other examples of such compounds are listed in Table II. In each of these examples an 25 equivalent amount of the starting material of formula 1 wherein B is absent, listed therein, is used (if different) instead of the compound of formula 1 in which B is absent described in example 6; and an equivalent amount of the protected amino 30 acid of formula PG-AA-OH wherein PG is an a-amino protective group and AA is an amino acid residue of formula NHCHR5C(0) wherein R5 is as defined herein, as listed in Table II, instead of the protected amino acid described in example 6. 37 25 12 67 PCT/CA93/00096 TABLE II Entry No. Entry No. of Starting Material of Formula 1 in Table I of Example 6 Protected Amino Acid Of Formula PG-AA-OH Product s N-fcert-3utyl-l-{3(S)-{{N-?G-AA} amino} -2 (R) -iydrory-4-phenyl-5uty1}-r-piperidine-2 f S1-carboxamide PG AA PG-AA//X 1 1 Z Val benzyloxycarbonyl)-valyl//4(R)-phenylthio) (689)* 2 1 z Asn benzylocarbonyx)-asparaginyl//4 (R)-(phenylthio) (704.3) 3 1 Boc Asn ;tert-butyloxycarbonyl) asparaginyl// 4(R)-(phenylthio) (670) 4 2 Z Val |benzyloxycarbonyl)-valyl//4(R)-phenyl (657) 5 2 Z He ;benzyloxycarbonyl)-isoleucyl//4(R)-phenyl (671) 6 2 Z Asn (benzyloxycarbonyl)-asparaginyl//4(R)-phenyl (672) 7 3 Z Val (benzyloxycarbonyl)-valyl//4(R)-benzyl (671) 8 4 Z Val (benzyloxycarbonyl)-valyl//4(R)-(phenylsulf onyl) (721) 9 4 Z Asn (benzyloxycarbonyl)-asparaginyl//4(R)-(phenylsulfonyl) (736) 10 5 Z Val (benzyloxycarbonyl)-valyl//4(R)-phenoxy (673) 11 5 Z Asn (benzyloxycarbonyl)-asparaginyl//4(R)-phenoxy (688) 12 6 Z Val (benzyloxycarbonyl)-valyl//4(R)-(2-pyridinyloxy) (674) 13 7 Z Val (benzyloxycarbonyl)-valyl//4(R)-cyclohexyl (663) WO 93/18003 38 25 12 67 PCT/CA93/000r TABLE II (continued) Entry Mo. Entry Mo. of Starting Material of Formula 1 in Table I of Example 6 Protected Amino Acid Of Formula PG-AA-OH Product:N-tert-Butyl-l--{3 (S)-{-{N-PG-AA}amino}-2 (R)-iydroxy-4-phenyl-suty1>-r-piperidine-2(S)-carboxamide PG AA PG-AA//Y 14 8 Z Val benzyloxycarbonyl)-valyl//4(R)-(2-pyridinylthio) (690) 15 9 Z Val (benzyloxycarbonyl)-valyl//4(R)-(4-pyridiny1thio) (690) 16 10 Z Val (benzyloxycarbonyl)-valyl//4(R)-(2-pyri-midinylthio) (691) 17 11 Z Val (benzyloxycarbonyl)-valyl//4(R)-{(4,6-dimethy1-2-pyr imidi-nyl)thio} (719) 18 12 Z Val (benzyloxycarbonyl)-valyl//4(R)-(benzyl-thio) (703) 19 13 Z Val (benzyloxycarbonyl)-valyl//4(R)-{(4-py-ridinylmethyl)thio} (704) 20 14 Z Val (benzyloxycarbonyl)-valyl//4(R)-{(3-py-ridinylmethyl )thio} (704) 21 16 Z Val (benzyloxycarbonyl)-valyl//4(R)-{(2-py-ridinylmethyl )thio} (704) The number in parenthesis' following the designation of the product for each entry is the found (M + H)+ from the FAB mass spectrum of the product. 25 12 67 WO 93/18003 PCT/CA93/00096 39 BxaropJLe 7 Preparation of N-tert-Butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}-5 butyl} -4 (R) - (phenylthio)piperidine-2(S)-carboxamide (formula 1; X = 2-quinolinylcarbonyl, B = Val, R1 = H, R2 = C(CH3)3 and Y = PhS) A solution of the title compound af section A 10 of example 6 (167 mg, 0.255 mmol) in 6 N HCl/dioxane (2.0 mL) was stirred at room temperature for 20 min. The solvent was removed under reduced pressure. The residue, a white solid, was drieu under high vacuum for 20 min to give the corresponding deprotected 15 amine as a hydrochloride salt. The latter salt was dissolved in CH2C12 (2 mL). DIEA (89 jxL, 0.510 mmol), 2-quinolinecarboxylic acid (48.6 mg, 0.280 mmol) and BOP (135 mg, 0.306 mmol) were added to the solution of the salt. The reaction mixture was 20 stirred at room temperature for 3.5 h while the pH of the mixture was maintained at 8 by periodic verification and the addition of DIEA when required. Thereafter, the reaction mixture was diluted with EtOAc and washed successively with a saturated 25 aqueous solution of NaHC03 (2X), H20 (2X) and brine. The organic layer was dried (MgS04) and concentrated to dryness under reduced pressure. The resulting colorless oil was purified by flash chromatography (Si02, eluent: hexane-EtOAc, 2:3) to give the title 30 compound as a white solid (161 mg, 89%). FAB mass spectrum, jn/z: 710 (M + H)+. By following the procedure of example 7, or by following the coupling procedure of section B of 35 example 6 in the instance when the starting material 25 12 67 WO 93/18003 PCT/CA93/OOOP' 40 is a compound of formula 1 vherein B is Asn, but replacing the title compound of section A of example 6 or the title compound of example 5, respectively, with the appropriate compound of formula 1 wherein B 5 is the divalent radical —NHCHRSC(0)- wherein R5 is as defined herein, X is a commonly used N-protective group, and R1, R2 and Y are as defined herein, and replacing 2-quinolinecarboxylic acid, or the protected amino acid Boc-Asn-OH (in section B of 10 example 6), respectively, with the appropriate carboxylic acid of formula X-OH wherein X is as defined herein, then the following compounds of formula 1 listed in TABLE III, are obtained. IS TABLE III Entry No. products N-tert-butyl-l-{3(S)-{N-{PG-AA> amino}-2(R)-hydroxy-4-phenylbuty1}-r-oiperidine-2(S)-carboxamide PG-AA//Y 1 (2-quinolinylcarbonyl)asparaginyl//4(R)-phenoxv (709)* 2 (2-quinolinylcarbonyl)asparaginyl//4(R)-(phenylsulfonyl) (757) 3 (2-quinolinylcarbonyX)asparaginyl//4(R)-(phenylthio) (725) 4 (2-naphthalenylcarbony1)valyl//4(R)-(phenylthio) (709) 5 (2-naphthalenylcarbonyl)asparaginyl)// 4(R)-(phenylthio) (724) * The number in parenthesis following the 20 designation of the product for each entry is the found (M + H)+ from the FAB mass spectrum of the product. 41 25 1 2 67 Example 8 Preparation of N-tert-Butyl-l-{2 (R)-hydroxy-4-phenyl-3 (S) -{ {N-{ (2-pyridinylmethoxy)carbonyl>iso-leucyl}amino}butyl}-4 (R)-phenylpiperidine-2 (S )-carboxamide (formula 1; X = 2-pyridinylmethoxycarbo-nyl, B = lie, R1 = H, R2 - C(CH3)3 and Y = Ph ) N-tert-butyl-l-{3(S)-amino-2 (R)-hydroxy-4-phenylbutyl} -4 (R) -phenylpiperidine-2 (S) -carboxamide {prepared by hydrogenolysis (5% Pd/C, 1 atmosphere, MeOH, 2h) from 0.605 mg (0.108 mmol) of N-tert-butyl-1-{ 3 (S) - (benzyloxycarbonylamino) -2 (R) -hydroxy-4-phenylbutyl}-4 (R) -phenylpiperidine-2 (S) -carboxamide (see entry 1 of Table I)} was dissolved in DMF (1.6 mL). The lithium salt of K-{(2- pyridinylmethoxy) carbonyl} isoleucine (586 mg, 0.228 mmol), 1-hydroxybenzotriazole (32 mg, 0.237 mmol) and N-ethyl-u/-{ 3- (dimethylamino) propyl }carbodiimide (45.4 mg, 0.237 mmol) were added to the solution. The mixture was stirred at room temperature for 18 h. Thereafter, the reaction mixture was diluted with Et20, washed with H20f a saturated aqueous solution of NaHC03 (2X) and brine, dried (MgS04) and evaporated to dryness. The resulting yellow oil was purified by flash chromatography (Si02, eluent: CHC13, MeOH, 97.5:2.5 and then 95:5) to give the title compound as a white solid (58.7 mg). FAB mass spectrum, m/z: 672 (M + H)+. Example 9 Preparation of N-tert-Butyl-l-{2(R)-hydroxy-3(S)-{H-{ {N-methyl-N- (2-pyridinylmethyl) amino} carbonyl }- valyl}-4-phenylbutyl}-4 (R)-(phenylthio)piperi A\V ' \V 9 JUL 1G3-r,: 25 12 67 WO 93/18003 PCT/CA93/000r 42 2(S)-carboxamide (formula 1; X = R3NR4C(0) wherein R3 = (2-pyridinylmethyl) and R4 = CH3, B = Val, R1 = H, R2 = C(CH3)3 and Y = PhS) 5 A solution of 1.9M phosgene in toluene (9.41 mL, 17.89 mmol) was added to a suspension of H-Val-0CH3*HC1 (1.0 g, 5.96 mmol). The reaction mixture was heated at reflux for 2 h under a dry ice condenser, cooled to room temperature, sparged 10 vigorously with nitrogen for 1.5 h and then concentrated to dryness. Toluene (5 mL) was added to the residue and the resulting solution concentrated to dryness to give (S)-2-isocyanato-3-methylbutanoic acid methyl ester. This product was 15 dried under high vacuum for 5 min and then used in the following step. XH NMR(CDC13) 6 3.95 - 3.94 (d, J » 3.82Hz, 1H), 3.81 (s, 3H) , 2.35 - 2.22 (m, 1H) , 1.04 - 1.02 (d, J = 6.8Hzf 3H), 0.91 - 0.89 (d, J = 6.74Hz, 3H). 20 The latter product (471 mg, 3.00 mmol) was dissolved in toluene (5 mL). N-Methyl-N-(2-pyridinylmethyl)amine {366 mg, 3.00 mmol, described by A. Fischer et al., Can. J. Chem., 3059 25 (1978)} was added to the solution. The resulting mixture was stirred under N2 at 90* for 16 h. The solvent was evaporated and the residue was purified by flash chromatography (Si02, eluent: EtOAc—MeOH, 24:1) to yield N-{{N-methyl-N-(2-pyridinylmethyl)-30 amino)carbonyl)valine methyl ester (616 mg, 73%) as an orange oil. *H NMR(CDC13) 5 8.58 - 8.55 (d, 1H), 7.72 - 7.65 (t, 1H), 7.29 - 7.19 (m, 2H), 6.20 - 6.05 (broad s, 1H), 4.55 (s, 2H), 4.45 - 4.40 (m, 1H), 3.71 (s, 3H) , 3.04 (s, 3H), 2.21 - 2.12 (m, 35 1H), 1.0 - 0.92 (dd, 6H). 25 12 67 WO 93/18003 PCT/CA93/00096 43 A solution of 1 N LiOH (1.72 mL; 1.72 iranol) was added, via a syringe pump, over a period of 3 h to a vigorously stirred solution of the last named ester (400 mg, 1.43 mmol) in dioxane (4 mL) and H20 (1 mL) 5 at room temperature. The reaction mixture was stirred at room temperature for 18 h and then evaporated to dryness. The residue was pulverized and dried over P2O5 under high vacuum to yield the lithium salt of N-{{N-methyl-N-(2-pyridinyl-10 methyl)amino)carbonyl}valine (390 mg; 100%). The latter lithium salt was coupled with N-tert-butyl-1-{3(S)-amino-2(R)-hydroxy-4-phenylbut-y1}-4(R)-(phenylthio)piperidine-2(S)-carboxamide 15 (prepared by the hydrogenolysis of the compound of entry 1 of Table II) according to the coupling procedure of example 8 to give the title compound of this example. FAB mass spectrum, m/zi 703 (M + H) + . 20 Example 10 Preparation of N-tert-Butyl-l-{3(S)-{{(2,6-dimethyl-phenoxy)acetyl}amino)-2(R)-hydroxy-4-phenylbutyl>-25 4(R)-{(3-pyridinylmethyl)thio}piperidine-2(S)-car- boxamide (formula 1; X = (2,6-dimethy lphenoxy) acetyl, B is absent, R1 = H, R2 = C(CH3)3 and Y is (3-pyridinylmethyl)thio) 30 The corresponding N-Boc derivative of the product described in entry 14, Table I of example 5 was converted to its corresponding primary amine, i.e. N-tert-buty1-1-(3(S)-amino-2(R)-hydroxy-4-phenylbutyl )-4(R)-{(3-pyridinylmethyl)thio}piperidine-2-35 carboxamide, by removal of the Boc protecting group 251267 WO 93/18003 PCT/CA93/OOOr 44 in the usual manner. The primary amine was isolated in the form of its trishydrochloride salt. The latter compound (154 mg, 0.27 mmol), (2,6-dimethylphenoxy)acetic acid (55.1 mg, 0.31 mmol) and 5 BOP (147 mg, 0.33 mmol) were mixed in anhydrous DMF (4 mL). DIEA (185 (iL, 1.06 mmol) was added to the mixture. The mixture was stirred at room temperature for 10 min. Another portion of DIEA (95 liL, 0.55 mmol) was added and the mixture was stirred 10 at the same temperature for 18 h. The reaction mixture was diluted with EtOAc (25 mL), washed successively with a saturated aqueous solution of NaHC03, HjO and brine, dried (MgS04) and concentrated to dryness. The residue was purified by flash 15 chromatography (Si02, eluent: gradients of .1% Et OH/EtOAc to 5% EtOH/EtOAc) to give the title compound as a pale yellow solid (107 mg, 64%); FAB mass spectrum, m/zi 633 (M + H)+. 20 Example 11 Recombinant HIV Protease HPLC Assay: Enzvme s HIV protease was expressed in E. coli 25 {construct pBRTl prt+, see W.G. Farmerie et al., Science, 236. 305 (1987)), according to the following protocol: Unless stated otherwise, all solutions are aqueous solutions. 30 (i) Fermentation 35 E. coli cells containing the pBRTl prt+ plasmid were used to inoculate a seed culture media composed of Luria-Bertani Broth containing 100 jig/mL of 25 12 67 WO 93/18003 PCT /C A93/00096 45 ampicillin. Flasks were incubated at 37* under agitation for 17 h. Production flasks containing sterile M9 broth, supplemented with 100 jxg/mL of ampicillin, were inoculated at a level of 1% (v/v) 5 ufsing the seed culture described above. Total volume in each production flask was 500 mL in a 2 L Erlenmeyer flask. Flasks were incubated at 37* under agitation until a cell concentration corresponding to an optical density (X = 540 [im) of 10 0.6 was reached (no dilution). This time span was routinely 3-4 h. Flasks were then supplemented with 5 mM isopropylthiogalactoside (IPTG., Research Organics, Cleveland, Ohio, USA) and incubation was continued until the cell concentration reached an 15 optical density of 0.2 at 16-fold dilution. Flasks were then supplemented with 1 mM phenylmethyl-sulfonyl fluoride (PMSF) and rapidly chilled to 4*. The bacterial cells were recovered by centrifugation at 4#. The wet pellet was stored at -70*. 20 (ii) Extraction and Preparation Assay Grade Engyme 25 All steps below were perfomed at 4* unless otherwise indicated. Thawed cells were mixed with buffer A {50 mM tris(hydroxymethyl)aminoethane HC1 (Tris-HCl, pH 7.4); 0.6 mM ethylenediamine-tetraacetic acid (EDTA); 0.375 M NaCl, 0.2% Nonidet 30 P-40 ® (BDH Chemicals Ltd., Poole, UK); 1 mM PMSF}, at a ratio of one part cells to nine parts buffer A. Diatomaceous earth (Celite 545 ®, John Manville, Lompoc, CA. USA) was added at a ratio of two parts to one part of wet cell weight. The resulting 35 slurry was homogenized at high speed (ca. 20,000 25 12 67 WO 93/18003 J _ PCT/CA93/000?' 46 rpm) on a Waring ® industrial blender for 8 x 15 sec. pulses. Cell debris/Celite ® was collected by centrifugation and the resulting pellet was extracted with 4.5 parts of buffer A to one part wet 5 solids using the hoinogenization procedure described above. Supernatants from both homogenization steps were combined and soluble protein was precipitated by the addition of solid (NH4)2S04 to yield a final concentration of 75% saturation. This mixture was 10 agitated for 60 min and the precipitate was recovered by centrifugation. The resulting pellet was suspended in buffer B {50 mM Tris-HCl, pH 8; 30 mM NaCl; 1 mM DL-dithiothreitol (DTT); 1 mM EDTA; 1 mM PMSF; 10% glycerol}, and dialyzed for 18 h 15 against the same buffer. An aliquot of the dialyzed extract containing 150 mg of the protein was loaded onto a Sephadex A25® anion exchange column (Pharmacia, Uppsala, 20 Sweden) with bed dimensions of 70 cm length and 2.5 cm diameter. The sample was eluted isocratically with buffer B at a linear flow rate of 10 cm/h. Fractions containing HIV protease activity (see below for assay description) were combined, and 25 soluble protein was precipitated by the addition of saturated aqueous (NH4)2S04 to yield a total (NH4)2S04 concentration of 85% saturation. Precipitated protein was remove,! by centrifugation and the resulting pellet was dissolved in buffer C 30 {50 mM 2-(4-morpholino)ethanesulfonic acid (MES), pH 5.5; 150 mM NaCl; 1 mM DTT; 1 mM EDTA; 10% glycerol}. This preparation was dialyzed for 18 h against buffer C, and then frozen at -70*. All crude extracts were purified by chromatography in 35 aliquots containing 150 mg of protein in the same WO 93/18003 47 25 12 67 PCT/CA93/00096 manner as described above. The final preparations from each batch were pooled, divided into 34 fiL aliquots and stored at -70°. The final protein recovered from a 20 L fermentation was typically 300 5 mg with a specific activity for HIV protease of 18.2 mmoles of substrate cleaved/min/mg. The aliquots were diluted to 1/38 of the original concentration with buffer, see below, prior 10 to use (i.e. the enzyme working solution). Substrate; VBFNFPQITL-NH2, MW 1164, see Krausslich et al., Proc. Natl. Acad. Sci. USA, 86. 807 (1989), was used as substrate. The substrate 15 was made into 10 mM stock in DMSO and stored at 4*. Prior to use, the stock was diluted with buffer to give a 400 pM solution (i.e. the substrate working solution). 20 Buffers MES (100 mM), KC1 (300 mM) and EDTA (5 mM) were dissolved in distilled H20 (90 mL) and the solution was adjusted to pH 5.5 with concentrated aqueous NaOH. The latter solution was diluted to 100 mL with H20 to give the buffer. 25 Procedure: (1) The assay mixture was prepared by mixing 20 pL of the substrate working solution, 10 |*L of the solution of the test compound in 10% DMSO and 10 fiL of the enzyme working solution. (2) The 30 assay mixture was incubated at 37° for 30 min. (3) The reaction was quenched by adding 200 jiL of 2% aqueous trifluoroacetic acid. (4) The substrate and products (i.e. VSFNF and PQITL-NH2) were separated by subjecting 100 nL of the quenched assay 35 mixture to HPLC using a Per kin-Elmer 3x3 CRC8 25 12 67 WO 93/18003 PCT/C A93/0009' 48 column (Perkin Elmer Inc., Norwalk, CT, USA) with a stepwise gradient at a flow rate of 4 mL/min. The gradient is as follows: 5 0.0-0.5 minutes, 70% A / 30% B; 0.5 - 3.0 minutes, 67% A / 33% B; 3.0 - 5.0 minutes, 20% A / 80% B; 5.0 - 6.5 minutes, 70% A / 30% B; 10 where A is 3 mM sodium dodecyl sulfate / 0.05% H3P04 in H20 and B is 0.05% H3P04 in acetonitrile. Elution was monitored at 210 nM. (5) A control, which was the assay mixture without the test compound, was subjected simultaneously to steps 2 to 4. 15 Inhibition Studies: Cleavage products and remaining parent substrate were quantified by either peak height or by integration of the appropriate HPLC peaks. Substrate conversion was calculated using 20 the following relationship: % Conversion = Sum of peak height or peak area of products X 100 25 Sum of peak height or peak area of substrate and products Enzyme inhibition of the test compound was calculated as follows: 30 % Inhibition = 100 - % Conversion for assay mixture X 100 % Conversion of control 35 The concentration of the test compound which causes a 50% inhibition of the HIV-protease, i.e. the IC50, was determined as follows: The percent inhibition of the enzyme was determined for a WO 93/18003 49 25 12 67 PCT/CA93/00096 minimum of three different concentrations of the test compound. Thereafter, the IC50 was determined graphically by plotting the percent inhibition of the enzyme against the concentration of the test 5 compound. The IC5o's of some exemplified compounds of formula 1, as determined in the recombinant HIV protease HPLC assay, are listed in Table IV, 10 following the next example. EXflTOPlQ 1? The following protocol, used for screening 15 antiviral effects of the compounds of formula 1, is adapted from a plaque assay utilizing HTLV-I transformed cells, previously reported by Harada et al., supra. HTLV-I transformed cells are used because of the rapidity with which HIV will 20 replicate in the cells. 1. The test compound is dissolved in dimethylsulf oxide to a concentration of 5 mg/mL. The resultant solution can be stored at 4 * until 25 use. 2. The resultant solution is diluted in RPMI 1640 (Gibco Laboratories, St. Lawrence, MA, USA) to four times (4X) the final concentration which is to be 30 tested. Once diluted in RPMI 1640, the solution is used in the cell culture assay within 4 h. 3. The 4X solution (50 jxL) is added to triplicate wells of a 96 well flat bottomed microtiter plate. 35 RPMI (50 pL) also is added to control wells. WO 93/18003 50 25 12 67 PCT/CA93/000P' 4. C8166 cells (5 x 104) in 50 jaL of HEPES-buffered RPMI 1640 (pH — 7.2), 10% heat, inactivated fetal calf serum (FCS), 12.5 pL/mL gentamicin 5 (complete media) are added to all wells. 5. Fifty times TCID50 of H9/HTLV-IIIB stock (stored in liquid nitrogen as cell culture supernatant in 50% FCS) in 100 pL of complete media is 10 added to all wells. Infectious titer of virus stocks are as previously determined by end point dilution on C8166 cells. Titer of stocks are stable for 6-12 months when stored at -193*. 15 6. Microtiter plates are then placed on level shelves of a 37*, 5% C02 humidified incubator for 72 h. 7. Plates are then removed and centers of syncytia 20 are counted in each well by low power phase contrast light microscopy. Each cluster of cells which shows evidence of any syncytia formation is counted as one center of syncytia. Control wells should have between 25 and 75 centers of syncytia per well. 25 8. Percent inhibition of syncytia formation is calculated by the formula: 30 % inhibition = 100 x/# syncytial centersj-(# syncytial centers in^ V in control wells J V test wells 35 ~p~~ /# syncytial centers in I control wells WO 93/18003 51 25 12 67 PCT/CA93/00096 The concentration of the test compound which causes a 50% inhibition of syncytia formation, i.e.the EC50, is determined by using the technique of serial dilution of the working solution at step 3 5 and by using non-linear regression analysis (SAS® program) to graphically plot the observed percent inhibition of syncytia formation against the various concentrations of the test compound. 10 In the following Table IV, assay results are listed for exemplified compounds of formula 1 from the recombinant HIV protease HPLC assay of example 10, i.e. IC50(nM) , and from the plaque assay of example 11, i.e. EC50 (nM). Note that for some of 15 the compounds listed in Table IV, the EC50's have not been determined (ND). TABLE IV 20 ENTRY NO. COMPOUND ICso (nM) ECso (nM) 1 N-tert-butyl-1-{3(S)-(benzyloxy-carbonylamino)-2(R) -hydroxy-4-(4-fluorophenyl)butyl}-4(R)-(phenylthio )piperidine-2(S)-carboxamide (described in example 5) 9.5 ND 2 N-tert-butyl-1—{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4— phenylbutyl>-4(R)-phenylpiperi-dine-2(S)-carboxamide (Table I,entry 1) 400 ND 3 N-tert-butyl-1-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-benzylpiperi-dine-2(S)-carboxamide (Table I,entry 2) 460 ND 4 N-tert-butyl-1-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(phenylsulfo-ny1)piperidine-2(S)-carboxamide (Table I,entry 3) 30 1400 52 TABLE IV (continued) ENTRI HO. COMPOUND ic50 (nM) EC50 (nM) 5 N-tert-butyl-1-{3(S)-(benzyloxy-carbonylami.no) -2 (R) -hydroxy-4-phenylbutyl}-4(R)-(phenylthio)-piperidine-2(S)-carboxamide (Table I, entry 4) 10 800 6 N—tert-butyl-l-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenoxypiperidi-ne-2(SJ-carboxamide (Table I,entry 5) 53 ND 7 11- tert-butyl-1- { 3 (S) - (benzy loxycarbonyl amino)-2 (R)-hydroxy-4-phenylbutyl}-4(R)-cylohexylpiperi-dine-2(S)-carboxamide (Table Xr entry 7) 2100 ND 8 N-tert-butyl-l-{-3(S)-{{N-benzyl-oxycarbonyl)valyl}amino}-2(R)-hydroxy-4-phenylbutyl>-4(R)-(phenylthio)piperidine-2(S)-carboxamide (Table II, entry 1) 3.9 13 9 N-ter t-butyl-1-{3(S)-{{N-(benzyloxycarbonyl )asparaginyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(phenylthio) p ?.per idine-2 (S) -carboxamide (Table II, entry 2) 4 43 10 N-tert-butyl-l-{3(S)-{{N-(benzyl-oxycarbonyl)valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenylpiperidine-2(S)-carboxamide (Table II, entry 4) 3.1 90 11 N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl )is oleucy1}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenylpiperidine-2(S)-carboxamide (Table II , entry 5) 3.7 700 12 N-ter t-butyl-l-{3(S)-{N-(benzyloxycarbonyl )asparaginyl} amino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenylpiperidine-2(S)-carboxamide (Table II, entry 6) 6.3 150 13 N-tert-butyl-l-{3(S)-{N-(benzyloxycarbonyl) valyl} amino} -2 (R)-hydroxy~4-phenylbutyl}-4(R)— benzylpiperidine-2(S)-carboxamide (Table II, entry 7) 4.1 40 A V •; o WO 93/18003 53 25126 PCT/ CA93/00096 TABLE IV (continued) ENTRY HO. COMPOUND ICso (nM) ECS0 (nM) 14 N-tert-butyl-l-{3(S)-{N-(benzyloxycarbonyl )valyl}amino}-2(R)-hydroxy-4-phenylbutyl} - 4 (R) -(phenylsulfonyl)piperidine-2(S)-carboxamide (Table IX, entry 8) 2.3 40 15 N-tert-butyl-l-{3(S)-{N-(benzyloxycarbonyl )asparaginyl}amino}-2(R)-hydroxy-4-phenylbuty1} - 4 (R) -(phenylsulfonyl)piperidine-2(S)-carboxamide (Table IZ, entry 9) 2.9 1270 16 N-tert-butyl-1-{3(S)-{N-(benzyl-oxycarbonyl)valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) -phenoxypiperidine-2 (S) -carboxamide (Table II, entry 10) 2.7 150 17 N-tert-butyl-l-{3(S)-{N-(benzyloxycarbonyl )asparaginyl}amino}-2(R)-hydroxy-4-phenylbuty1}-4(R)-phenoxypiperidine-2(S)-carboxamide (Table II, entry 11) 2.5 42 18 N-tert-butyl-1-{3(S)-{N-(benzyloxycarbonyl) valyl} amino) -2 (R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyridinyloxy)piperidine-2(S) -carboxamide (Table II, entry 12) 1.8 . 56 19 N-tert-butyl-l-{3(S)-{N-(benzyloxycarbonyl) valyl} amino} -2 (R) — hydroxy-4-phenylbutyl}-4(R)-cyclohexylpiperidine-2(S)-carboxamide (Table II, entry 13) 8 200 20 N-tart-buty1—1-{2(R)-hydroxy-4-phenyl-3(S)-{(N-(2-quinolinylcarbonyl )valyl}amino}butyl} - 4 (R) -(phenylthio)piperidine-2(S)-carboxamide (Title compound of example 7) 3.1 12 21 N-tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcar-bonyl)asparaginyl} amino}butyl}-4(R)-phenoxypiperidine-2(S)-carboxamide (Table III, entry 1) 5.4 15 WO 93/18003 54 25 1 2 PCT/CA93/000r TABLE IV (continued) ENTRY NO. COMPOUND IC50 (nM) EC50 (nM) 22 N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl )asparaginyl)amino)butyl}-4(R)-(phenylsulfonyl)piperidine-2(S)-carboxamide (Table III, entry 2) 4.7 450 23 N-tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcar-bonyl)asparaginyl)amino>butyl>-4(R)-(phenylthio)piperidine-2(S)-carboxamide (Table III, entry 3) 1.8 10 24 N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-naphtha-lenylcarbonyl)valyl}amino)butyl>-4(R)-(phenylthio)piperidine-2(S)— carboxamide (Table III, entry 4) 2.3 16 25 N-tert-butyl-l-{2(R)-hydroxy-3(S)-{{N-(2-naphthalenylcarbonyl)asparaginyl) amino) -4-phenylbutyl) -4(R)-(phenylthio)piperidine-2(S)-carboxamide (Table III, entry 5) 1.9 33 26 N-tert-buty1-1-{3(s)—{{N-(benzyloxycarbonyl )valyl)amino}-2(R)-hydroxy-4-(4-fluorophenyl)butyl)-4(R)-(phenylthio)piperidine-2(S)-carboxamide(described in example 6) 3.5 24 27 N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-{(2-pyridinylmethoxy )carbonyl}isoleucyl) amino)-butyl}-4(R)-phenylpiperidine-2(S)-carboxamide (Title compound of example 8) 4.9 500 28 N-tert-butyl—l-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl)-4(R)-(2-pyridinyl-thio)piperidine-2(S)-carboxamide (Table I,entry 8) 16 500 29 N-tert-butyl-l-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl)-4(R)-(4-pyridinyl-thio)piperidine-2(S)-carboxamide (Table I,entry 9) 8 140 ^ WO 93/18003 55 251 26 PCT/CA93/00096 TABLE IV (continued) ENTRY NO. COMPOUND IC50 (nM) BCso (nM) 30 N-tert-buty1-1-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyrimidinyl-thio)piperidine-2(S)-carboxamide (Table I,entry 10) 19 822 31 N-tert-butyl-1-{3(S)-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4,6-dimethyl-2-pyrimidinylthio)-piperidine-2(S)-carboxamide (Table X, entry 11) 12 290 32 N-tert-buty1-l-{3(?^-(benzyloxy-carbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(benzylthio)-piperidine-2(S)-carboxamide (Table I,entry 12) 10 ND 33 N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl) valyl} amino} -2 (R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyridinylthio)piperidine-2(S)-carboxamide (Table II, en cry 14) 3.2 11 34 N-tert-buty1-1-{3(S)-{{N-(benzyloxycarbonyl )valyl} amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) -(4-pyridinylthio)piperidine-2(S)-carboxamide (Table XX, entry 15) 2.5 11 35 N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl )valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) -(2-pyrimidinylthio)piperidine-2(S)-carboxamide (Table II, entry 16) 3.7 15 36 N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl )valyl} amino}-2(R)-hydroxy— 4—phenylbutyl}-4(R) -(4,6-dimethyl-2-pyrimidinylthio)piperidine-2 (S)-carboxamide (Table II, entry 17) 3.0 9 37 N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl) valyl} amino}-2 (R)-hydroxy-4-phenylbutyl}-4(R) -(benzylthio)piperidine-2(S) -carboxamide (Table II, entry 18) 2.3 7 56 2 5 1 % 6 7 L I TABLE IV (continued) ENTRY NO. COMPOUND (nM) EC,„ (nM) 38 N-tert-butyl-l-{2(R)-hydroxy-3(S)- , {N- {{N-methyl-N-(2-pyridinylmethyl )amino}carbonyl}valyl}-4-phenylbutyl}-4(R)-(phenylthio)-piperidine-2(S)-carboxamide (Title compound of example 9) 4.3 14 Other compounds of formula 1 prepared by the processes disclosed herein are listed in Tables V, VI and VII together with characterizing mass spectral data and the assay results for the compounds from the recombinant HIV protease HPLC assay of example 11, i.e. IC50 (nM) and from the plaque assay of example 12, i.e. EC50 (nM). TABLE V ENTRY NO. Compound of fbrmula 1 having the formula N-tert-butyl-l-{2(r)-hydroxy-4-phenyl-3(S)-{{N-(2-quinol-ylinylcarbonyl)valyl}-amino}butyl}-Y-piperidine-2 (S)-carboxamide wherein Y is as desiqnated hereinbelow fab/ms (m/z) (m+h)+ ic5n (nM) ecro (nM) 1 4 (R)-(2-pvrimidinylthio) 712 3.6 7 2 4 (R)-{(4-pyridinylmethyl)-thio} 725 2.0 4 3 4 (R)-(2-PYridinYlmethoxy) 709 3.9 24 4 4(R)—{(4,6-dimethyl-2-pvrimidinyl)thio} 740 2.7 8 i 9 JUL 1996 57 251 TABLE V (continued) ENTRY No. Compound of formula 1 having the formula N-tert-buty 1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinol-ylinylcarbonyl)valyl}amino} butyl}-y-piperidine-2 (S)-carboxamide wherein Y is as designated hereinbelow FAB/MS (m/z) (M+H)+ icsn (nM) ECS0 (nM) 5 4(R)-(4-pyridinylthio) 711 1.5 3 6 4 {R) - (2-pyridinylthio) 711 1.9 4 7 4(R)-phenoxy 694 3.4 14 8 4(R)-{{3-pyridinylmethyl)-thio} 725 2.2 3 9 4(R)-{(2-pyridinylmethyl)~ thio} 725 4.2 5 10 4(R)-(2-pyrimidinyloxy) 696 3:2 25 11 4(R)—{(4,6-dimethyl-2-pyri-midinyl)oxy} 724 4.0 20 12 4(R)-{(4-methyl-2-pyri-midinyl}oxy> 710 4.5 44 13 4(R)-{(2,6-dimethyl-4-pyri-midinyl)oxy} 724 3.6 17 14 4(R)-(phenylsulfonyl) 756 2.9 23 15 4(R)-{(4-fluorophenyl)oxy> 712 2.6 22 16 4(R)-(4-pyridinylmethoxy) ' 709 4.2 22 17 4(R)-{(2-pyridinylmethyl)-sulfonyl} 757 2.4 33 18 4(R)-{(3-pyridinylmethyl)-sulfonyl} 757 1.8 67 19 4(R)-{(4-pyridinylmethyl)-sulfonyl} 757 4.6 73 20 4(R)-(2-pyridinylsulfonyl) 743 1.7 r !si 'n U 9 JU v 58 TABLE V (continued) ENTRY No. Compound of formula 1 having the formula' N-tert-butyl-1-{2 (R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinol-ylinylcarbonyl)valyl}amino} butyl }-r-piperidine-2(S) -carboxamide wherein Y is as desigi^ited hereinbelow FAB/MS (m/z) (M+H)+ icsn (nM) ECS0 (nM) 21 4(R)-(4-pyridinvlsulfonyl) 743 1.7 25 22 4(R)-{(2,6-dimethyl~4-pyri-midinyl}thio} 740 2.4 11 23 4(R)-{(4-methyl-2-pyrimi-dinyl)thio} 726 2.8 16 24 4(R)-(3-pyridinylmethoxy) . 709 3.7 53 TABLE VI ENTRY No. Compound of formula 1 having the formula N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolylinylcarbon-yl}B}amino}butyl}-y-pipe- ridine-2(S)-caiboxamide wherein B and Y are as designated hereinbelow fab/ms (m/z) (m+h)+ ^50 (nM) -tezt-but-ylqlycyl 4(R)-(phenyl-thio) 724 3.0 asparaginyl 4(R)-{(4,6-dime-thyl-2-py-rimidiny1)}thio 755 2.2 59 1 2 677 TABLE VI (continued) ENTRY NO. Compound of formula 1 having the formula N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinol-ylinylcarbonyl)B} amino}butyl} -^-.piperidine-2 (S) -carboxamide vherein B and Y are as desi<5K5»tc<d hereinbelow FAB/MS (m/z) (M+H)+ ic50 (nM) ECsn (nM) i B 1 Y 3 asparaginyl 4(R)-(2-pyrimi-dinylthio) 727 2.1 60 4 - (N'-meth-yl)aspara-qinvl 4(R)-phenoxy 723 3.7 13 5 -tert-but-ylglycyl 4(R)-{(3-pyridinylmethyl ) -thio} 740 2.2 8 6 threonyl 4(R)-(phenylsulf onyl) 744 2.6 61 7 -tert-but-ylqlycyl 4(R)-(4-pyri-dinylsulfonyl) 757 2.1 29 8 -tert-but-vlqlvcyl 4(R)-(2-pyri-dinylsulfonyl) 757 2.9 44 WO 93/18003 60 25 12 6 7 PCT / C A93/0Q00 * TABLE VII ENTRY NO. Zompound of formula 1 having the formula N-tert-butyl-1-{3(S)-{{*} amino}"2(R)-hydroxy-4-phenylbutyl}-Y-pipf;ridine-2 (S) -carboxamide wherein X and y are as designated below FAB/MS (m/z) (M+H) + icR0 (nM) ECS0 (nM) X r 1* (2,6-di-methylphen-oxy)acetyl 4(R)-{(3-pyridinylmethyl ) -thio> 633 2.7 35 2 (2,4,6-tri-methylphen-oxy)acetyl 4(R)-(4-pyri-dinylthio) 633 3.7 47 3 phenoxya-cetyl 4(R)-(4-pyri-dinylthio) 591 34 ND 4 (2,6-di-methylphen-oxy)acetyl 4 (R)-(4-pyri-dinylthio) 619 3.1 20 5 (2-methyl-phenoxy)-acetyl 4(R)-(4-pyri-dinylthio) 605 6.2 140 6 {2,4-di-chlorophen-vl)carbonyl 4(R)-(4-pyri-dinylthio) 629 5.4 340 7 (2,5-di-chlorophen-vl)carbonyl 4(R)-(4-pyri-dinylthio) 629 9.8 360 8 (2,6-di-fluorophenyl )carbonyl 4(R)-(4-pyri-dinylthio) 597 14 340 WO 93/18003 61 25 12 67 PCT/CA93/00096 TABLE VII (continued) ENTRY No. Compound of formula 1 having the formula N-tert-butyl-1-{3(S)-{{X}amino}-2(R)-hydroxy-4-phenylbuty1}- Y-piperidine-2(S)-carboxamide wherein X and Y are as designated below FAB/MS (m/z) (M+H)+ IC5o (nM) ECsn (nM) X y 9 (5-fluoro-2-methyl-phenyl)carbonyl 4(R)-(4-pyri-dinylthio) 593 6.8 ND 5 * Preparation of the compound of entry 1 is described in example 10. Other compounds of formula 1 include: 10 N-tert-buty1-1-{2(R)-hydroxy-4-pheny1-3(S) -{{N-(2-quinolinylcarbonyl)asparaginyl> amino}butyl>-4(R)-(4— pyridinylthio)piperidine-2(S)-carboxamide 15 N-tert-butyl-l-{4-(4-fluorophenyl)-2(R)-hydroxy- 3(S)-{{N-(2-naphthalenylcarbonyl)valyl> amino}butyl}-4 (R)-(2-pyrimidinylthio)piperidine-2(S)-carboxamide N-tert-butyl-1-{2(R)-hydroxy-4-pheny1-3(S)-{{N-(2-20 pyridinylcarbonyl)valyl}amino}butyl}-4(R)-phenoxypiperidine-2(S)-carboxamide </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 25 12 67 WO 93/18003 PCr/CA93/OOOp 62 N-tert-butyl-1-{2 (R)-hydroxy-4-phenyl-3(S)-{{N-(2-pyridinylcarbonyl)asparaginyl> amino}butyl}-4(R)-phenoxypiperidine-2(S)-carboxamide WO 93/18003 63 25 12 67 PCT/CA93/00096 10 CLAIMS:

1. A compound of formula 1 X-B-N! C(0)NHR 1 wherein X is R30C(0), R3C(0) or R3NR4C(0) wherein R3 is 15 (i) lower alkyl, (ii) lower cycloalkyl, (iii)phenyl; phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; or disubstituted phenyl 20 wherein each of the two substituents is independently lower alkyl or halo; (iv) phenyl(lower)alkyl or phenyl(lower)-alkyl wherein the aromatic portion thereof is monosubstituted with halo, 25 hydroxy, lower alkyl or lower alkoxy, (v) 1-naphthyl or 2-naphthyl, (vi) (Het) or (Het)-(lower alkyl) wherein Het represents a five or six membered, monovalent heterocyclic 30 radical containing one or two hetero- atoms selected from nitrogen, oxygen and sulfur, or (vii)2-quinolinyl or 3-guinolinyl, and R4 is hydrogen or lower alkyl; or 35 X is R3A0CH2C(0) wherein R3A is phenyl, or monosubstituted, disubstituted or trisubstituted phenyl wherein eaich substituent is independently lower alkyl or halo; 25 1 2 67 5 10 15 20 25 64 13 is absent or the divalent radical -NHCHRsC(0)-wherein R5 is lower alkyl; lower cycloalkyl; (lower cycloalkyl")-(lower alkyl); phenylmethyl; or lower alkyl monosubstituted with hydroxy, carboxy, lower alkoxycarbonyl, aminocarbonyl, (lower alkyl) aminocarbonyl or di(lower alkyl)aminocarbonyl; R1 is hydrogen, halo, hydroxy, lower alkyl or lower alkoxy; R2 is lower alkyl; and Y is lower alkyl; lower cycloalkyl; phenyl or phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; benzyl or benzyl monosubstitued with halo, hydroxy, lower alkyl or lower alkoxy; or Y is W(CH2)nZ wherein W is oxo, thio, sulfinyl or sulfonyl, z is lower alkyl; phenyl or phenyl monosubstituted with halo, hydroxy, lower alkyl or lower alkoxy; or (Het) wherein (Het) is as defined in this claim, and n is zero or one; or a therapeutically acceptable acid addition salt thereof; wherein the term "lower alkyl**, either alone or in combination with another radical, means a straight chain alkyl radical containing from 1 to 6 C atoms or a branched chain alkyl radical containing 3 or 4 C atoms; the term "lower cycloalkyl", either alone or in combination with another radical, means a saturated cyclic hydrocarbon radical containing fron 3 to 6 C atoms; and the term "lower alkoxy" means a straight chain alkoxy radical containing from 1 to 6 C atoms or a branched chain alkoxy radical containing 3 or 4 C atoms. /V i 9 JUL 1996' 25 12 6 7 65

2. A compound as defined in claim 1 vherein X is R30C(0), R3C(0) or R3NR4C(0) wherein R3 is lower alkyl, , phenyl, 2,4-dimethylphenyl, 2,6- dimethylphenyl, 2,4-dichlorophenyl, 2,5-dichloro-5 phenyl, 2,6-difluorophenyl, 5-f luoro-2-methylphenyl, phenyl(lower)alkyl, phenyl(lower)alkyl wherein position 4 of the phenyl portion is substituted with chloro, fluoro, hydroxy, methyl or methoxy; 1-naphthyl, 2-naphthyl, 2-furyl, 2-thienyl, 2-10 pyridinyl, 4-pyridinyl, 2-pyridinylmethyl, 4-thiazolylmethyl or '2-quinolinyl, and R4 is hydrogen or lower alkyl;or X is R3A0CH2C(O) wherein R3A is phenyl or phenyl mono-, di- or trisubstituted with lower alkyl or 15 halo at a position or positions selected from the group consisting of positions 2, 4 and 6; B is absent or is the divalent radical -NHCHR5C(0)-wherein R5 is lower alkyl, or lower alkyl monosubstituted with hydroxy, lower alkoxycarbonyl, 20 aminocarbonyl, (lower alkyl) aminocarbonyl or di(lower alkyl)aminocarbonyl; R1 is hydrogen, chloro, bromo or fluoro;. R2 is 1-methylethyl, 2-methylpropyl or 1,1-dimethylethyl; and 25 Y is lower cycloalkyl, phenyl, 4-chlorophenyl, 4-bromophenyl, 4-fluorophenyl, 4-methylphenyl, 4— methoxyphenyl, benzyl, (4-fluorophenyl)methyl, (4-methoxy-phenyl)methyl or (4-methylphenyl)methyl; or Y is W (CH2) nZ wherein W and n are as defined 30 in claim 1 and Z is lower alkyl, phenyl, 2-furyl, 2-thienyl, 2-pyridinyl, 3-pyridinyl, 4-pyridinyl, 4-thiazolyl, 2-pyrimidinyl, 4-methyl-2-pyrimidinyl, 4,6-dimethyl-2-pyrimidinyl or 2,6-dimethyl-4-pyrimidinyl; or a therapeutically acceptable acid 35 addition salt thereof- p 3 JUL las' 66 £ 5 1 Z I ^

3. A compound as defined in claim 2 wherein X is tert-butyloxycarbonyl, (2,6-dimethylphen-yl)carbonyl, (2,4-dichlorophenyl)carbonyl, (2,5-5 dichlorophenyl)carbonyl,- (2,6-difluorophenyl)carbonyl, (5-fluoro-2-methylphenyl)carbonyl, benzyloxycarbonyl, (4-chlorophenyl)methoxycarbonyl, (4-hydroxyphenyl)methoxycarbony1, (4-methoxyphenyl)- methoxycarbonyl, acetyl, benzoyl/ 1-naphthalen-10 ylcarbonyl, 2-naphthalenylcarbonyl, (2-pyridinylmethoxy )carbonyl, 2-quinolinylcarbonyl, benzylamino-carbonyl, N-( 2-pyridinylmethyl) aminocarbonyl, N-methyl-N- (2-pyridinylmethyl) aminocarbonyl, phenoxy-acetyl, (2-methylphenoxy)acetyl, (2,4- 15 dimethylphenoxy)acetyl, (2,6-dimethylphenoxy)acetyl, (2,4,6-trimethylphenoxy)acetyl, (4-chlorophenoxy)-acetyl or (4-fluoro-2,6-dimethylphenoxy)acetyl; B is absent or the divalent radical -NHCHR5C(0)-wherein R5 is 1-methylethyl, 1,1-dimethylethyl, 1-20 methylpropyl, 2-methylpropyl, 1-hydroxyethyl, (methoxycarbonyl) methyl, (ethoxycarbonyl)methyl, (aminocarbonyl)methyl or {(methylamino)carbonyl}-methyl; R1 is hydrogen or fluoro R2 is 2- methylpropyl or 1,1-dimethylethyl; and Y is 25 cyclohexyl, phenyl, 4-chlorophenyl, 4-fluorophenyl, 4-methoxyphenyl, benzyl, (4-methylphenyl)methyl, (4- methoxyphenyl)methyl, 2-methylpropoxy, phenoxy, 2-pyridinyloxy, 3-pyridinyloxy, 4-pyridinyloxy, 2-pyrimidinyloxy, (4-methyl-2-pyrimidinyl)oxy, (4,6-dimethyl-2-pyrimidin-30 yl)oxy, (2,6-dimethyl-4-pyrimidinyl)oxy, benzyloxy, 2-pyridinylmethoxy, 3-pyridinylmethoxy, 4- pyridinylmethoxy, 4-thiazolylmethoxy, phenylthio, phenylsulfinyl, phenylsulfonyl, 2-pyridinylthio, 3-pyridinylthio, 4-pyridinylthio, 2-pyrimidinylthio, 35 (4-methyl-2-pyrimidinyl)thio, (2,6-dimethyl-4-pyri- & U 9 JUL 1996 1M 25 1 26 7 o / midinyl)thio, (4,6-dimet hyl-2-pyrimidinyl)thio, benzylthio, benzylsulfinyl, benzylsulfonyl, (2-pyridinylmethyl)thio, (3-pyridinylmethyl)thio or (4-pyridinylmethyl)thio; or a therapeutically 5 acceptable acid addition salt.

4. A compound as defined in claim 3 wherein X is tert-butyloxycarbonyl, benzyloxycarbonyl, acetyl, (2,6-dimethylphenyl)carbonyl, 2-naphthalenylcarbon-10 yl, (2-pyridinylmethoxy)carbonyl, 2-quinolinyl carbonyl or {N-methyl-N-(2-pyridinylmethyl)amino}-carbonyl; B is valyl, tert-butylglycyl, isoleucyl, threonyl or asparaginyl; R1 is hydrogen or fluoro; R2 is 1,1-dimethylethyl; and Y is phenyl, benzyl, 15 phenoxy, 2-pyrimidinyloxy, (2,6-dimethyl-4- pyrimidinyl)oxy, 2-pyridinylmethoxy, 3-pyridin-ylmethoxy, 4-pyridinylmethoxy, phenylthio, phenylsulfinyl, phenylsulfonyl, 2-pyridinylthio, 3-pyridinylthio, 4-pyridinylthio, 2-pyrimidinylthio 20 (4,6-dimethyl-2-pyrimidinyl)thio, (2-pyridinylmeth yl) thio, (3-pyridinylmethyl)thio or 4-(pyridinyl- ; methyl)thio; or a therapeutically acceptable acid addition salt thereof. 25

5. A compound as defined in claim 3 wherein X is (2-methylphenoxy)acetyl, (2,4-dimethylphenoxy)- acetyl, (2,6-dimethylphenoxy) acetyl or (2,4,6"-dimethylphenoxy)acetyl; B is absent; R1 is hydrogen; R2 is 1,1-dimethylethyl; and Y is phenyl, benzyl, 30 phenoxy, 2-pyrimidinyloxy, 2-pyridinylmethoxy, 3- pyridinylmethoxy, 4-pyridinylmethoxy, phenylthio, phenylsulfinyl, phenylsulfonyl, 2-pyridinylthio, 3-pyridinylthio, 4-pyridinylthio, 2-pyrimidinylthio (4,6-dimethyl-2-pyrimidinyl)thio, (2-pyridinylmeth^, 35 yl)thio, (3-pyridinylmethyl)thio or 4-(pyridi 68 25 1 2 6 7 methyl)thio; or a therapeutically acceptable acid addition salt thereof.

6. A compound as claimed in claim 1 selected from the group of: N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R) -hydroxy-4-(4-fluorophenyl)butyl>-4(R)-(phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-(benzyloxycarbonylamino)-2(R) -hydroxy-4-phenylbutyl>-4(R)-phenylpiperidine-2(S) -carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-benzylpiperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl>-4(R)-(phenylsulfonyl)-piperidine-2(S)-carboxamide, N-tert-buty1-1-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl>-4(R)-(phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl>-4(R)-phenoxypiperidine-2(S)-"carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-cylohexylpiperidine-2(S)-carboxamide, 69 N-Cert-butyl-l-{-3(S) -{ {N-,(benzyloxycarbonyl) -valyl}amino}-2(R)-hydroxy—4—phenylbutyl}-4(R)-(phenylthio) piperidine-2 (S.)-carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-asparaginyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) (phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-valy1}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenylpiperidine-2(S)—carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-isoleucyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenylpiperidine-2(S)-carboxamide, N-tert-buty1-1-{3(S)-{{N-(benzyloxycarbonyl)-aspar ag iny 1} aihino} -2 (R) -hydroxy-4 -phenylbutyl} -4 ( R) phenylpiperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-benzylpiperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(phenylsulfonyl)piperidine-2(S)-carboxamide, N-tert-buty1-1-{3(S)-{{N-(benzyloxycarbonyl)-asparaginyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) (phenylsulfonyl)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl)-valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenoxypiperidine-2(S)-carboxamide, r. . .. . -i, i n i -■ o / 70 N-tert-butyl-1-{3(S)-{{N~(benzyloxycarbonyl)- n asparaginyl> amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-phenoxypiperidine-2(S)-carboxamide, 5 N-tez*t—butyl-l-{3 (S) -{ {N-(benzyloxycarbonyl) - valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)—(2-pyridinyloxy)piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{N-(benzyloxycarbonyl)-10 valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) — cyclohexylpiperidine-2(S)-carboxamide, N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{ {N- (2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-15 (phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-pheny1-3(S)-{{N-(2-quinolinylcarbonyl)asparaginyl}amino}butyl}-4(R)-phenoxypiperidine-2(S)-carboxamide, 20 N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbony1)asparaginyl}amino}butyl}-4(R)-(phenylsulfonyl)piperidine-2(S)-carboxamide, 25 N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)asparaginyl}amino}butyl}-4(R)-(phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-30 naphthalenylcarl onyl) valyl}aunino}butyl}-4 (R)-(phenylthio)piperidine-2(S)-carboxamide, N-tert-buty1-1-{2(R)-hydroxy-3(S)-{{N-(2-naphthalenylcarbonyl)asparaginyl}amino}-4-35 phenylbutyl}-4(R)-(phenylthio)piperidine-2- carboxamide, 9 JUL 1996 If 251267 N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl)-valyl}amino>-2(R)-hydroxy-4-(4-fluorophenyl)butyl}-4(R)-(phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-{(2-pyridinylmethoxy)carbonyl}isoleucyl} amino}butyl}-4(R)-phenylpiperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyridinyl-thio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyridinylthio)-piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyrimidinyIth io)-piperidine-2{S)-carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4,6-dimethyl-2-pyrimidinylthio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-(benzyloxycarbonylamino)-2(R)-hydroxy-4-phenylbutyl}-4(R)-(benzylthio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-{(N-(benzyloxycarbonyl)-valyl} amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(2-pyridinylthio)piperidine-2(S)-carboxamide, 72 25 1 2 6 7 N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl)-valyl} amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)—{4 — pyridinyl.t hio) piperidine-2 (S) -carboxamide, N-tert-buty1-1-{3(S)-{{N-(benzyloxycarbonyl)-valyl} amino}—2(R)-hydroxy-4-phenylbutyl}-4(R)2-pyrimidinylthio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-{{N-(benzyloxycarbonyl)-valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-{4,6-dimethyl-2-pyrimidinyr thio)piperidine-2(S)-carboxamide, N-tert-butyl-l-{3(S)-{(N-(benzyloxycarbonyl)-valyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(benzylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{2(R}-hydroxy-3(S)- {N-{[ N-methyl-N-(2-pyridinylmethyl)amino]carbonyl}valyl}-4-phenylbutyl}-4(R)—(phenylthio)piperidine-2(S)-carboxamide, N-tert-butyl—l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)—(2— pyrimidinylthio)piperidine-2(S)-carboxamide, N-tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(4-pyridinylmethyl)thio}piperidine-2(S)-carboxamide, N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-{2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-(2-pyridinylmethoxy) piperidine- 2 (S.1): -carboxamide, 73 251 N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}—4(R)-{(4,6-dimethyl-2-pyrimidinyl)thio}piperidine- 2 (S) -carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N~(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-(4-pyridinylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}bu tyl}-4(R)-(2-pyridinylthio)piperidine-2(S)-carboxamide, N-tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-phenoxy-piperidine-2(S)-carboxamide, N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(3-pyridinylmethyl)thio}piperidine-2(S)-carboxamide, N-tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)~{(2-pyridinylmethyl) thio}piperidine- 2 (S) -carboxamide, N-tert-buty1-l-{2(R)-hydroxy-4-pheny1-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-(2-pyrimidinyloxy)piperidine-2 (S) -carboxamide, N-tert-butyl—1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-H 2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(4,6— dimethyl-2-pyrimidinyl )oxy} piperidine-2 fS)-carboxamide, 74 Or /: O ? *T do I li \J / 5 10 15 20 30 N-tez"t-butyl-l-{2 (R) -hydroxy-4-phenyl-3 ( S) -{ {N-( 2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(4-me t hy 1 -2 -py r imidiny 1) oxy > piperidine- 2 (S) -carboxamide, N-tert-butyl-1—{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4 (R) -{ (2, 6-dimethy 1-4-pyrimidiny 1) oxy } piper idine-2 (S) -carboxamide, N-tert-butyl-l-{2 (R)-hydroxy-4-phenyl-3 (S) -{{N-( 2-quinolinylcarbonyl)valyl}amino} buty 1} -4 (R) -(phenylsulf onyl) piperidine- 2 (S) -carboxamide, N- ter t-buty 1-1- { 2 (R) -hydroxy-4 -phenyl- 3(S)-r{{N-(2-quinolinylcarbonyl)valyl}amino}butyl>-4(R) -{(4-f luorophenyl) oxy } piperidine- 2 (S) -carboxamide, N-tert-butyl-1-{2 (R) -hydroxy-4-phenyl-3 (S} -{ {N-( 2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-(4-pyridinylmethoxy) piperidine- 2 (6) -carboxamide, N- tert-buty 1-1- { 2 (R) -hydroxy-4 -phenyl-3 (S) - { { N- (2 -quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(2-pyridinylmethyl) sulfonyl}piperidine-2 (S) -carboxamide, N- tert-butyl-1- { 2 (R) -hydroxy-4 -phenyl-3 (S) - { {N- (2 -quinolinylcarbonyl)valyl}amino}butyl}-4(R) -{(3-pyridinylmethyl) sulfonyl}piperidine-2 (S)-carboxamide, N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-{(4-pyridinylmethyl) sulfonyl} piperidine-2 (S) -carboxamide, N-tert-butyl-l-{2 (R) -hydroxy-4-phenyl-3 (S) -{{N-( 2-quinolinylcarbonyl)valyl}amino}butyl}-4(R)-(2-pyridinylsulf onyl) piperidine- 2 (s) -carboxamide, 75 251267 N-tert-butyl-1-(2(R)-hydroxy-4~pheny1-3(S)-{{N-(2-quinolinylcarbonyl )valyl}ajmino>butyl}-4 (R)-(4-pyridinylsulfonyl) piperidine-2 (S) -carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl} amino}butyl}-4(R)-{(2,6-dimethyl-4-pyrimidinyl) thio}piperidine- 2(S)-carboxamide, N- tert-butyl-1-{2(R}-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valy1}amino}butyl}-4(R)-{(4-methyl-2-pyr imidinyl) thio} piperidine- 2 (S) -carboxamide, N- tert-buty1-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)valyl} amino}butyl}-4(R)-(3-pyridinylmethoxy)piperidine- 2 (S) -carboxamide, N- ter t-butyl-1- { 2 (R) -hydroxy-4 -pheny 1- 3 (S )-{{*«-( 2-quinolinylcarbonyl)-tert-butylglycyl}amino}butyl}-4(R)-(phenylthio)piperidine-2(S)-carboxamide, N- ter t-buty 1-1- { 2 (R) -hydroxy-4 -phenyl-3 (S) - { {N- (2-quinolinylcarbonyl)asparaginyl}amino}butyl}-4(R)-{(4,6-dimethy1-2-pyrimidinyl)thio}piperidine- 2 (S) -carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)asparaginyl}amino}butyl}-4(R)-(2-pyrimidinylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-(2 (R)-hydroxy-4—phenyl-3 (S)-{ {N-(2~ quinolinylcarbonyl) - (N4-methyl) -asparaginyl}amino}-butyl}-4(R)-phenoxypiperidine-2(S)-carboxamide, 76 25 30 25 12 6 7 N-tert-butyl-1-{ 2 (R) -hydroxy-4-phenyl-3 (S)-{{N-(2r-quinolinylcarbonyl)-tert-butylglycyl}amino}butyl}-4(R)—{(3-pyridinylmethyl)thio}piperidine-2(S) carboxamide, 5 N-terd-butyl-1-{2(R)-hydroxy-4-phenyl-3 (S)-{{N-(2-quinolinylcarbonyl)threonyl}amino}butyl}—4(R)— ^ (phenylsulfonyl)piperidine-.2 (S) -carboxamide, 10 N-tert-butyl-l-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-quinolinylcarbonyl)-tert-butylglycyl}amino}butyl}-4 (R)-(4-pyridinylsulfonyl)piperidine-2 (S) -carboxamide, N-tert-butyl-1-{2(R)-hydroxy-4-phenyl-3(S)-{{N-(2-15 quinolinylcarbonyl)-tert-butylglycyl}amino}butyl}- 4(R)-(2-pyridinylsulfonyl)piperidine- 2 (S)-carboxamide, N-tert-butyl-1-{3(S)-{{(2,6-dimethylphenoxy)acetyl}-amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-{(3-pyridin-20 ylmethyl)thio}piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{(2,4,6-trimethylphenoxy)— acetyl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyridinylthio)piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(5)-{(phenoxyacetyl)amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyridinylthio)-piperidine-2(S)-carboxamide, N-tert-butyl-1-{3(S)-{{(2,6-dimethylphenoxy)acetyl}-amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyridin-y1thio)piperidine-2(S)-carboxamide, 2 5 12 6 7 77 N-tert-butyl-1-{3(S)-{{(2-methylphenoxy) acetyl }-amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyridin-ylthio)piperidine-2(S)-carboxamide, N— tert—butyl—1 — { 3 {S) -{ { (2,4-dichlorophenyl)carbonyl} amino >-2(R)-hydroxy-4-phenylbutyl>-4(R) - (4 -pyridinylthio) piperidine-2 (S) -carboxamide, N- tert-butyl-l-{ 3 (S)— { { (215-dichlorophenyl) carbonyl} amino}-2(R)-hydroxy-4-phenylbutyl}-4(R)-(4-pyr idinyl thio) piperidine-2 (S) -carboxamide, N-tert-butyl-1-{3 (S)-{{ (2,6-dif luorophenyl)carbon-yl}amino}-2(R)-hydroxy-4-phenylbutyl}-4(R) — (4 — pyridiny1thio)piperidine-2(S)-carboxamide, and N-tert-butyl-1-{3(S)-{{(5-fluoro-2 -methylphen-yl)carbonyl}amino}-2 (R)-hydroxy-4-pheny lbutyl}-4 (R)-(4-pyridinylthio)piperidine-2 (S)-carboxamide.

7. A pharmaceutical composition comprising a compound as recited in claim 1, or a therapeutically acceptable salt ^thereof, and a pharmaceutically acceptable carrier.

8. A compound as defined in any of claims 1 to 6, or a therapeutically acceptable salt thereof, for treating HIV infections in a human-

9. A compound as defined in any of claims 1 to 6, or a therapeutically acceptable salt thereof, for protecting human cells against HIV pathogenesis. fv 'hi Q SMI J J OL S-V $CF. 78 251 2 6

10. A process for preparing a compound of formula 1 as defined in claim 1, or a therapeutically acceptable acid addition salt, comprising: (a) reacting an epoxide of formula 2 X-NH i Ft 10 2 wherein X and R1 are as defined in claim 1 with a piperidinecarboxamide of formula 3 rr HN J r C (O) NHR2 3. 15 wherein R2 and Y are as defined in claim 1 to obtain the corresponding compound of formula 1 wherein Xf R1, R2 and Y are as defined in this claim and B is absent; or (b) reacting a compound of formula 4 20 C(0)NHRZ 25 4. wherein R1, R2 and Y are as defined in' this claim with a reactive derivative of the carboxylic acid X- OH wherein X is R3C(0) or R3A0CH2C(0) as defined in claim l to obtain the corresponding compound of 30 formula 1 wherein X is R3C(0) or R3A0CH2C(0) as defined in this claim, and R1, R2 and Y are as defined in this claim and B is absent; or 9 JUL 13961 79 25 1 2 6 7. (c) coupling the compound of formula 4 wherein R1, R2 and Y are as defined in this claim with an a-amino acid of the formula X-NHCHR5COOH wherein X is as defined in this claim and R5 is as defined in claim 1, in the presence 5 of a coupling agent to obtain the corresponding compound of formula 1 wherein X, R1, R2 and Y are as defined in this claim and B the divalent radical - NHCHR^C(0)- wherein is as defined in this claim; or 10 (d) reacting a compound of formula 5 H2NCHR5C(0)NH 15 C(0)NHR2 5. wherein R1, R2, R5 and Y are as defined in this claim 20 with a reactive derivative of the carboxylic acid X-OH wherein X is R3C(0) or R3AOCH2C(0) as defined in this claim to obtain the corresponding compound of formula 1 wherein X is R3C(0) or R3A0CH2C(O) as defined in this claim, R1, R2 and Y are as defined 25 in this claim and B is the divalent radical -NHCHR5C(0)- wherein R5 is as defined in this claim; and (e) if desired, transforming the compound of 30 formula 1, as obtained in the preceding sections (a), (b), (c) or (d), into a corresponding therapeutically acceptable acid addition salt. </div>